Sonic screwdriver

The sonic screwdriver — often called the sonic — was a highly versatile tool used by many, but not all, incarnations of the Doctor. The Doctor modified and ostensibly upgraded it over the years, giving it an increasing number of applications. Early versions were used mainly for the picking of locks and for projecting sound so as to, for example, detonate bombs. By the time of the Ninth Doctor, the sonic was able to also be used as a sophisticated scanning device, with medical applications. Subsequent incarnations gave it even wider functionality, such as the ability to hack into computers, provide geolocation and actively defend against some types of assault weapon.

All of these incarnations utilised the same software, though they used different cases. For all intents and purposes, the War Doctor's sonic was the same as the Eleventh Doctor's some 400 years later. (TV: The Day of the Doctor)

Technology and functions
The sonic screwdriver was considered to be very advanced Gallifreyan technology. (PROSE: Heart of TARDIS) The First Doctor built the first sonic screwdriver (or an innovative model of one) instead of wooing a woman, something he later regretted. (TV: A Christmas Carol) His ninth incarnation suggested that the First Doctor did it partially out of boredom. (TV: The Doctor Dances) Other alien races had similar devices, such as the sonic pen used by Miss Foster (TV: Partners in Crime) and the sonic blaster obtained by Captain Jack Harkness and River Song. (TV: The Empty Child / The Doctor Dances, Silence in the Library / Forest of the Dead)

At least one version of the screwdriver used a crystal similar to the Metebelis crystal sought after by the Eight Legs of Metebelis III. (COMIC: The Forgotten) There were also electrical components. (COMIC: The Halls of Sacrifice)

The screwdriver had a multitude of settings and different versions of settings. The Tenth Doctor told Rose to use "setting 15B" to triangulate the source of the ghosts (TV: Army of Ghosts) and used 34-H to sink a ship (COMIC: Second Wave). It had a setting 85 that undid security codes to unlock doors. (TV: The Lazarus Experiment) The Ninth Doctor told Rose to use setting 2428D to re-attach barbed wire. (TV: The Doctor Dances) Sarah Jane used the Theta Omega setting to melt plastic vines. (TV: The Android Invasion)

The different versions of the Doctor's sonic screwdrivers exhibited different capabilities and uses, such as the interception of signals ranging from transmat beams to conscious thought; (TV: The End of the World) medical diagnostics and repair of organic parts; (TV: The Empty Child, The Vampires of Venice) cutting, but also re-attaching materials such as barbed wire; (TV: The Doctor Dances) operating Earth machinery such as computers and even cash machines (at regular and high eject speeds); (TV: School Reunion, The Runaway Bride) creating a spark to light a candle or Bunsen burner; (TV: The Girl in the Fireplace, Evolution of the Daleks) opening and holding doors with acoustic locks; (TV: The Rings of Akhaten) and, on the rare occasion, driving screws without touching them. (TV: The War Games, The Ark in Space, The Doctor's Wife)

Although it was primarily a tool, the sonic screwdriver could also be used as a defensive weapon. The Tenth Doctor put it in a sound board to destroy the Robot Santas by overloading their sensors. (TV: The Runaway Bride) The Eleventh Doctor used it to bounce sound waves off a knife held by Melody Pond, knocking it out of her hand. (TV: Let's Kill Hitler) The sonic screwdriver was also capable of holding off sound waves from creatures who relied on sound in order to attack such as the Vigil. (TV: The Rings of Akhaten) The Doctor also used it to try and help River Song defeat a group of Silents although River teased him by saying it would be better if he used it to "build a cabinet". However, the Doctor implied that although it couldn't actually hurt the Silents it could weaken the power of their electricity, therefore allowing him to provide River with a certain degree of protection while she shot down their foes. (TV: Day of the Moon)

Although the Eighth Doctor once claimed the device could destroy a Dalek's brain if held directly against the casing when activated, (PROSE: War of the Daleks) according to the Tenth Doctor, the device could not be used to wound, maim or kill living things. (TV: Doomsday, The Doctor's Daughter) It could destroy non-living objects or mechanisms or place living creatures in circumstances where they might die, if the situation required. (TV: The End of the World, The Christmas Invasion) The War Doctor claimed that it was a scientific instrument rather than a water pistol. (TV: The Day of the Doctor)

From time to time, the sonic screwdriver needed to be recharged. (TV: Silence in the Library / Forest of the Dead, PROSE: The Monsters Inside, COMIC: Bizarre Zero) It was self-repairing and could send out a homing signal to any parts that had been separated. (TV: A Christmas Carol) However, it was up to the owner to collect the parts for reassembly.

Sonic screwdrivers and similar technology could not unlock a deadlock seal. (TV: School Reunion) To undo one of these seals, the user would need at least two sonic devices. One such instance was when the Tenth Doctor used his own sonic screwdriver in conjunction with Miss Foster's sonic pen to open the deadlock seals on and within her own facility when the Doctor's screwdriver alone could not. (TV: Partners in Crime) Some or all versions were ineffective against wood, or in the presence of some models of hairdryers. (TV: Silence in the Library / Forest of the Dead, The Hungry Earth, Night Terrors, PROSE: Catastrophea)

The First and Second Doctor's sonic
One sonic screwdriver, a small, simple device similar to a penlight, used by the First (PROSE: Venusian Lullaby) and Second Doctor. (TV: Fury from the Deep) It was used by the Eighth Doctor after it was destroyed "centuries ago". He explained how this occurred to his companion Samantha Jones: "It's a Time Lord tool. Time doesn't work the same way for Time Lord tools." (PROSE: Alien Bodies)

Known uses

 * Cracking the code for an aerodynamic shuttle. (PROSE: Venusian Lullaby) 
 * Opening up hatches, panels and control panels. (TV: Fury from the Deep, The War Games)
 * For cutting through a section of a wall. (TV: The Dominators)
 * As a conventional screwdriver (without touching the screws). (TV: The War Games)

The Third Doctor's sonic
The Third Doctor's most-used model of the sonic screwdriver was much larger than the one his first and second incarnation used; its elaborately-detailed silver shape featured black and yellow stripes and red trim. It had a removable head which the Doctor would change with others, each performing a different function. (TV: The Sea Devils)

Known uses

 * Scanning for alarm systems in the Master's TARDIS. (TV: Colony in Space)
 * Remote detection and detonation of land mines. (TV: The Sea Devils)
 * To open an electronic door. (TV: The Mutants)
 * Creation of a spark of fire and igniting swamp gas. (TV: Carnival of Monsters)
 * Open electronic locks. (TV: Carnival of Monsters)
 * As conventional screwdriver, on large, flathead screw. (TV: The Curse of Peladon)
 * Overloading the brains of Space Greyhounds. (COMIC: The Forgotten)

Refit used by the Third, Fourth and Fifth Doctor
The Third Doctor fitted the head of his sonic screwdriver with a cylindrical black magnet which enabled it to open bolted doors, especially when its polarity was reversed. (TV: Frontier in Space) This refit left the metal mostly unpainted, with a dark red emitter ring. The head of this model could be extended. Before this model was destroyed, (TV: The Visitation) its head was repainted twice after the original coat wore off. (TV: The Keeper of Traken, Castrovalva) The Doctor went without a sonic screwdriver for some time after this model and Nyssa lamented the Fifth Doctor's decision not to replace it. (TV: Snakedance)

The Doctor, leaving UNIT, left behind a prototype. UNIT scientists then tried to use reverse-engineering to understand its workings; this went on into the 21st century. Despite them trying to keep it quiet from the Doctor, he was well aware of the project by his seventh incarnation. (AUDIO: Persuasion)

Known uses

 * Unbolting a door. (TV: Frontier in Space)
 * Fusing shut a sliding door. (TV: Planet of the Daleks)
 * Opening a lift door. (TV: The Green Death)
 * Distracting giant maggots. (TV: The Green Death)
 * Detecting boobytrapped floor tiles. (TV: Death to the Daleks)
 * Breaking a hypnotic trance. (TV: Death to the Daleks)
 * Opening a refinery door. (TV: The Monster of Peladon)
 * Remotely detonating mines. (TV: Robot)
 * Cutting locks. (TV: Robot)
 * Undoing screws. (TV: The Ark in Space)
 * Repairing wires chewed by the Wirrn. (TV: The Ark in Space)
 * Fixing a circle of transmat refractors. (TV: The Sontaran Experiment)
 * Breaching a force field. (TV: The Sontaran Experiment)
 * Shutting down Styre's robot. (TV: The Sontaran Experiment)
 * Sabotaging a two-way radio. (TV: Genesis of the Daleks)
 * Deactivating an energy loop opening up Sutekh's deflection barrier. (TV: Pyramids of Mars)
 * Shattering the Clynex. (COMIC: The Naked Flame)
 * Safecracking (TV: The Sun Makers)
 * Creating a temporary hole in Gallifrey's force field above the Citadel. (TV: The Invasion of Time)
 * Using the correct sonic frequency to return the Fourth Doctor, Ernestina Stott and later, his scarf, to normal size. (AUDIO: The Dead Shoes)
 * Opening doors on Ribos. (TV: The Ribos Operation)
 * Unlocking multi-levered interlocks to the Ribos crown jewels casket (TV: The Ribos Operation)
 * Opening the door to the real Queen Xanxia's chamber. (TV: The Pirate Planet)
 * Freeing Romana I from her bonds on a prison ship in hyperspace. (TV: The Stones of Blood)
 * Blowing up a Dalek bomb. (TV: Destiny of the Daleks)
 * Unscrewing the Zero Room's hinges and assisting in constructing the Zero Cabinet. (TV: Castrovalva)
 * Disarming fusion bombs by reversing the polarity of the neutron-flow. (PROSE: Cold Fusion)
 * Creating a piercing loud noise to prevent security cameras from picking on the conversation between the Fifth Doctor, Adric, Nyssa, and Tegan. (TV: Four to Doomsday)
 * Opening a door to escape confinement. (TV: Four to Doomsday)
 * Reversing the magnetic field on Monopticons. (TV: Four to Doomsday)
 * Short-circuiting androids in conjunction with a pencil, the graphite acting as a conductive material for the screwdriver's power. (TV: Four to Doomsday)
 * It was used as a component in the delta wave augmenter, to induce sleep. (TV: Kinda)

Used from the end of the Seventh Doctor's life
Towards the end of his seventh life, the Doctor fished another type of sonic screwdriver from one of the tool kits in the TARDIS. This model looked similar to the screwdriver seen at the end of his fourth incarnation; it was silver with a brass trim ring in the lower grip. The handle resembled the previous sonic screwdrivers with the upper section being able to collapse in similar fashion as a telescope into itself for ease of carrying. At the top, the emitter has a silver ring with a red bullet shape in the centre. This version remained in the Eighth Doctor's use throughout his life. Later, a torch was built into the handle. Once, while suffering from amnesia, the Doctor distracted himself and operated this sonic screwdriver on instinct.

At the end of his life during the Last Great Time War, the Eighth Doctor used a similar model. (TV: The Night of the Doctor)

Known uses

 * Locking the casket containing the Master's remains. (TV: Doctor Who)
 * Performing maintenance on new parts in the TARDIS console. (TV: Doctor Who)
 * Disorienting a Rescue Operational Security Module. (AUDIO: Embrace the Darkness)
 * Raising the bulkheads between Romana II and the Matrix chamber. (AUDIO: Neverland)
 * Jamming motion-sensitive sensors long enough for the Doctor and his companions to get to safety. (AUDIO: Scaredy Cat)
 * Locking the TARDIS console room away from the rest of the ship until it could repair itself during a Hellion attack. (AUDIO: Absolution)
 * Tracking residual energy traces. (AUDIO: The Girl Who Never Was)
 * Reactivating a long-dormant telegraph machine. (AUDIO: The Girl Who Never Was)
 * Opening the organic locks used by the Zygons. (PROSE: The Bodysnatchers)
 * Destroying a Dalek's brain (when placed directly against the Dalek's casing around its head). (PROSE: War of the Daleks)
 * Making Dalek weapons detonate. (PROSE: Legacy of the Daleks)
 * Repelling ghosts. (PROSE: Vanderdeken's Children)
 * Opening a door in a force field large enough for the Doctor and his companions to travel through. (PROSE: EarthWorld)
 * Opening the chest of the mobile nuclear weapon Fatboy. (PROSE: Eater of Wasps)
 * Decapitating the King of Beasts, leader of the Babewyn. (PROSE: The Adventuress of Henrietta Street)
 * Locking a bank vault from the inside. (PROSE: Trading Futures)
 * Temporarily disabling an electron bomb. (PROSE: The Tomorrow Windows)
 * Subduing hostile dogs. (PROSE: The Deadstone Memorial)
 * Disrupting the control signal for floating magnetic discs. (PROSE: To the Slaughter)
 * Turning Cybermen against each other. (COMIC: The Flood)
 * Oscillating the atoms of wickerwork to weaken the structure. (AUDIO: Dead London)
 * Vibrating Molluscari from their shells by duplicating the precise frequency necessary. (AUDIO: Orbis)
 * Weakening a stone wall by weakening the molecular bonds between atoms. (AUDIO: The Book of Kells)
 * Opening a bulk head door on a crashing spaceship. (TV: The Night of the Doctor)
 * Scanning for life signs. (TV: The Night of the Doctor)

After Lucie and Tamsin
Later in his eighth incarnation, the Doctor carried a sonic screwdriver with a wooden handle. It had a metallic tip with six prongs that nested a clear diode at the end, which glowed blue when activated. (AUDIO: The Great War) The Doctor claimed that he made this version of the sonic screwdriver to do more than open doors and blow up land mines. (AUDIO: X and the Daleks) It was called a pennywhistle by World War I medics. (AUDIO: The Great War)

Known uses

 * Fixing a train track. (AUDIO: The Great War)
 * Trying to shatter the walls of a prison. (AUDIO: Tangled Web)

The War Doctor's sonic
At the end of the War Doctor's life, the Doctor used a sonic screwdriver with a simple metallic handle and a red diode at the end. (TV: The Day of the Doctor)

Known uses

 * Implanting a permanent subroutine within the architecture of the sonic screwdriver's software that would begin the centuries-long calculation to disintegrate a door. (TV: The Day of the Doctor)
 * Activating the memory-erasing device in the Black Archive. (TV: The Day of the Doctor)

The Ninth and Tenth Doctor's sonic
The Doctor had yet another screwdriver during his eighth incarnation. This one had a glowing blue diode at one end. Although the Eighth Doctor was known to have used it as well, (PROSE: Osskah) this model was much more ubiquitous as the model carried by the Ninth Doctor, who used it far less frequently like his previous incarnations had done before. The Tenth Doctor also used this model, as he liked tinkering with technology to make devices he needed. This version was burnt out by accident after the Doctor used it to modify an X-ray output to over 5000%, but had replaced it with a near-identical model. (TV: Smith and Jones) The only visible difference was the colour scheme of the handle. The tenth incarnation had this screwdriver on his person during his regeneration, and was damaged repeatedly afterwards, which led to malfunctions. Despite the damage, the Eleventh Doctor used it to overload technology in an attempt to alert the Atraxi to Prisoner Zero's location. This fried it into useless, charred metal, much to his growing annoyance and anger. (TV: The Eleventh Hour)

Security

 * Opening a door. (TV: Aliens of London)
 * Freeing the Ninth Doctor from his manacles. (TV: The Long Game)
 * Unlocking handcuffs. (TV: The Doctor Dances)
 * Locking and unlocking a hatch in Cybus Industries (TV: The Age of Steel)
 * Unlocking a taxi door and window. (TV: The Runaway Bride)
 * Hacking into the H.C. Clements website. (TV: The Runaway Bride)
 * Bypassing the key needed to access the secret basement in H.C. Clements. (TV: The Runaway Bride)
 * Opening air-tight seals. (TV: Gridlock)
 * Unsuccessfully activating emergency by-pass switches. (TV: Gridlock)
 * Bypassing and turning off security systems. (TV: The Lazarus Experiment)
 * Disabling security orbs. (COMIC: Wrath of the Warrior)
 * Trying unsuccessfully to hack into New New York's police communications to call for help. (TV: Gridlock)
 * Destroying a security camera. (TV: The Sound of Drums)
 * Opening and closing the Titanic's doors. (TV: Voyage of the Damned)
 * Disabling emergency exit alarms and locks, but causing sparks as a result. (TV: Partners in Crime)
 * Controlling a cable cart; also locking it in a "sonic cage" to prevent anything but another sonic device from controlling it. (TV: Partners in Crime)
 * Breaking into a silo on the Ood-Sphere. (TV: Planet of the Ood)
 * Fusing a lock shut, forcing it to be broken down. (TV: ''Planet of the Ood)
 * Temporarily turning off lethal security beams. (TV: The Doctor's Daughter)
 * Opening the casing of a cleaning robot. (COMIC: Carnage Zoo)
 * Accessing Bowie Base One's records on the Flood infection. (TV: The Waters of Mars)
 * Unlocking the door to Adelaide Brooke's house. (TV: The Waters of Mars)
 * Switching the Hesperus' power off. (TV: The End of Time)
 * Locking Prisoner Zero in the room it was hiding in. (TV: The Eleventh Hour)
 * Opening bus doors. (TV: Planet of the Dead)
 * Unlocking handcuffs. (TV: Planet of the Dead, The Eleventh Hour)

Medical

 * Healing Osskah Longspan's body. (PROSE: Osskah)
 * Acting as a medical scanner and diagnostic tool. (TV: The Empty Child)
 * Dislodging and reinserting teeth. (COMIC: The Lodger)
 * Partially reversing the Abzorbaloff's absorption of Ursula Blake. (TV: Love & Monsters)
 * Confusing the antibodies of a living planet. (COMIC: Lonely Planet)
 * Building a DNA scanning device. (TV: Daleks in Manhattan)
 * Scanning for fluctuating DNA, specifically that of Professor Lazarus. (TV: The Lazarus Experiment)

Diagnostic

 * Detecting and stopping telepathic signals. (TV: Rose)
 * Scanning a life form for information, specifically Donna Noble. (TV: The Runaway Bride)
 * Detecting heated water. (COMIC: The Halls of Sacrifice)
 * Scanning shadows for the presence of Vashta Nerada. (TV: Silence in the Library/Forest of the Dead)
 * Checking Crusader 50's control console for faults. (TV: Midnight)
 * Scanning for Infostamps. (TV: The Next Doctor)
 * Tracing distress signals. (COMIC: The Ghost Factory)
 * Scanning slime. (COMIC: Doomsilk)
 * Scanning the President of Earth for alien influence. (COMIC: Return of the Klytode)
 * Detecting and illuminating ultraviolet characters. (PROSE: The Game of Death)
 * Detecting the arrival of spacecraft. (PROSE: The Pictures of Emptiness)
 * Picking up traces of psychic spoor. (COMIC: Mortal Beloved)
 * Detecting time traces. (TV: The Wedding of Sarah Jane Smith)
 * Scanning a crack in Amelia Pond's wall. (TV: The Eleventh Hour)
 * Detecting the progress of the War Doctor's calculation in his iteration of the sonic screwdriver. (TV: The Day of the Doctor)

Technology

 * Destroying the controls of a lift. (TV: Rose)
 * Establishing an interface with a computer. (TV: The End of the World)
 * Controlling a lift. (TV: World War Three)
 * Causing rain via atmospheric excitation. (COMIC: Death to the Doctor!)
 * Obtaining money from a cash machine. (TV: The Long Game)
 * Opening off a panel to Satellite Five's mainframe. (TV: The Long Game)
 * Getting money from a cash machine, at both regular and extra-high rates of ejection. (TV: The Runaway Bride)
 * Obtaining access to Satellite Five's core computer. (TV: The Long Game)
 * Charging from a battery. (TV: Father's Day)
 * Reversing teleport devices. (TV: Boom Town)
 * Destroying a television camera. (TV: Bad Wolf)
 * Dematerialising the TARDIS and initialising TARDIS processes from outside the craft. (TV: The Parting of the Ways)
 * Blowing up a remote control Christmas tree. (TV: The Christmas Invasion)
 * Reestablishing the time window's connection to a space ship in the future. (TV: The Girl in the Fireplace)
 * De-activating a living graphite scribble. (TV: Fear Her)
 * Reversing an anti-gravity umbrella. (COMIC: Smart Bombs)
 * Detonating an explosive device. (TV: Doomsday)
 * Detonating the head of a roboform. (TV: The Runaway Bride)
 * Searching a phone for an app or a feature. (TV: The Runaway Bride)
 * Summoning the TARDIS using Huon particles. (TV: The Runaway Bride)
 * Scanning through hospital records, specifically to find any patient suffering from strange symptoms (an alien in disguise). (TV: Smith and Jones)
 * Partially activating ventilation airducts. (TV: Gridlock)
 * Reversing the polarity of Lazarus' machine, sending an energy pulse out to knock Lazarus unconscious and revert him to human form. (TV: The Lazarus Experiment)
 * Disabling robotic flies. (COMIC: Exhausting Evil)
 * Modifying hearing aids. (COMIC: The Screaming Prison)
 * Reversing teleport feeds. (COMIC: Warriors' Revenge)
 * Giving mobile phones the ability to call across time and space. (TV: 42, Planet of the Dead, The Doctor's Daughter)
 * Completing the propulsion system for the ship destined for Utopia (TV: Utopia)
 * Fusing the TARDIS' navigational coordinates, allowing only travel between its current position and the previous one. The fusion was imperfect; at least 18 months before or after take-off were allowed as destinations. (TV: Utopia)
 * Fixing and upgrading a decades-broken vortex manipulator. (TV: Utopia)
 * Rewiring a television/portrait to show ship's systems. (TV: Voyage of the Damned)
 * Signalling that there was alien technology in Leadworth (during which the screwdriver itself exploded). (TV: The Eleventh Hour)
 * Looping temporal energy of a fraxis pod back into a zygma drive. (COMIC: Blooms of Doom!)
 * Shattering robot assassins. (COMIC: A Suitable Showdown)
 * Disabling a Sontaran teleport. (TV: The Sontaran Stratagem)
 * Unsuccessfully trying to bypass the Sontarans' control of the ATMOS, forcing the Doctor to use reverse-psychology with the machine to avoid drowning. (TV: The Sontaran Stratagem)
 * Changing the destination of a Sontaran teleport. (TV: The Poison Sky)
 * Changing the "channel" on a broadcast when the Sontarans began chanting. (TV: The Poison Sky)
 * Building a terraforming device to ignite the posionous clouds. (TV: The Poison Sky)
 * Accessing hidden areas on a holographic map. (TV: The Doctor's Daughter)
 * Unintentionally showing a hologram of Donna Noble. (TV: Forest of the Dead)
 * Tinting a helmet visor and increasing the mesh density of a spacesuit (TV: Forest of the Dead)
 * Disabling the Crusader 50's annoying entertainment system; this was a mercy to the Doctor himself and many other passengers. (TV: Midnight)
 * Modifying a gravity converter. (COMIC: Skydive!)
 * Disabling a Cyrronak robot. (COMIC: Highway Robbery)
 * Cancelling out a phonic blast. (COMIC: We Will Rock You)
 * Repairing an overloading distribution box. (PROSE: The Graves of Mordane)
 * Downloading a journal. (PROSE: The Colour of Darkness)
 * Remotely controlling environmental controls. (PROSE: The Game of Death)
 * Overriding Gadget's controller and increasing the robot's speed to the point where it left trails of flames behind. (TV: The Waters of Mars)
 * Disabling a Shimmer. (TV: The End of Time)
 * Helping repair the Hesperus. (TV: The End of Time)
 * Remotely controlling the TARDIS to change its course, saving the Doctor and his vessel the fate of colliding into Big Ben. (TV: The Eleventh Hour)
 * Opening a "crack" in space-time. (TV: The Eleventh Hour)
 * Switching a radio between several international channels to determine that the Atraxi were broadcasting their warning for Prisoner Zero to surrender or be destroyed along with the "human residence" to the entire Earth. (TV: The Eleventh Hour)
 * Activating the memory-erasing device in the Black Archive. (TV: The Day of the Doctor)

Amplification

 * Setting up a resonation pattern in concrete. (TV: The Doctor Dances)
 * Destroying the Robot Santas with sound (used in conjunction with a professional sound system). (TV: The Runaway Bride)
 * Increasing the radiation output of a device such as an x-ray scanner; this action burned out the screwdriver. (TV: Smith and Jones)
 * Producing hypersonic sound waves which led to the death of the mutated Richard Lazarus, in conjunction with a pipe organ. (TV: The Lazarus Experiment)
 * Used with Miss Foster's sonic pen to create an ultra-high frequency (TV: Partners in Crime)

Utility

 * Corroding thin metal (e.g. barbed wire) so that it crumbled into rust. (TV: The Doctor Dances)
 * Re-connecting barbed wire. (TV: The Doctor Dances)
 * Igniting swamp gas. (COMIC: The Hunt of Doom)
 * Stopping the emergence of Mirrorlings from mirrors. (COMIC: Mirror Image)
 * Lighting a candle. (TV: The Girl in the Fireplace)
 * Cutting rope. (TV: The Age of Steel)
 * Illuminating Rose Tyler. (COMIC: Warfreekz!)
 * Partially cracking glass so it could be smashed with the tiniest press of a finger. (TV: Army of Ghosts)
 * Cutting a spider web. (TV: The Runaway Bride)
 * Overloading Cybermen. (COMIC: The Power of the Cybermen)
 * Crashing an aircar. (COMIC: Time of the Cybermen)
 * Trying to strip off pieces of Dalekanium. (TV: Evolution of the Daleks)
 * Lighting a Bunsen burner from a distance. (TV: Evolution of the Daleks)
 * Melting hardened asphalt into heated tarmac, and reversing the process, so as to catch animals in a road (PROSE: The Last Dodo)
 * Sinking a ship. (COMIC: Second Wave)
 * Resonating a floor to destroy it, via crystal gems. (COMIC: Operation Lock-up)
 * Melting chocolate by increasing the resonance frequency of a torch. (COMIC: Crimes and Punishment)
 * As a soldering iron to make perception filters using TARDIS keys. (TV: The Sound of Drums)
 * Uncorking a champagne bottle. (TV: Voyage of the Damned)
 * Knocking over stone tablets. (TV: The Fires of Pompeii)
 * Cutting rope holding Donna to a sacrificial altar. (TV: The Fires of Pompeii)
 * Creating a stasis beam. (COMIC: School of the Dead)
 * Teleporting a Graske to the other side of the universe. (TV: Music of the Spheres)
 * Teleporting onto a Nim spacecraft. (COMIC: The Day the Earth Was Sold, The King of Earth)
 * As a sonic toothbrush. (COMIC: The Continuity Cap)
 * Shattering ice. (COMIC: Arctic Eclipse)
 * Blowing up a fire hydrant. (COMIC: Creature Feature)
 * Atmospheric excitation to cause rain. (COMIC: Mudshock)
 * Tickling a lion with sonic waves. (PROSE: The Slitheen Excursion)
 * Tinting the Doctor's glasses, effectively making them sunglasses. (TV: Planet of the Dead)
 * Stopping and winding up a winch. (TV: Planet of the Dead)
 * Incapacitating a Gizou. (COMIC: Fugitive)
 * Making toast and butter. (AUDIO: Dead Air)
 * As an actual screwdriver, without touching the screws. (TV: Dreamland, The Doctor's Daughter)

After Prisoner Zero
After the loss of the sonic screwdriver, the TARDIS gifted the Doctor with this new model. Differing radically from the last due to having "claws" and a green diode, rather than blue, it also had copper plating similar to the control room which had built itself following the TARDIS' crash landing in Leadworth. (TV: The Eleventh Hour) A psychic interface allowed its user to point it at a target and think of the function they wanted, instead of "settings"; however, it may have been a secondary way of using it. (TV: Let's Kill Hitler) Having been mentioned to be more than sonic, (TV: Night Terrors) this screwdriver also shot beams of green energy. (TV: Day of the Moon, Closing Time)

Retaining ineffectiveness against wood, it also didn't work against Peg Dolls (TV: Night Terrors) or the Wooden King and Queen. (TV: The Doctor, the Widow and the Wardrobe) The Doctor considered it embarassing and that "I need to invent a setting for wood." (TV: Night Terrors) In similar situations, he yelled at it in panic; "Aliens made of wood, you know this was always going to happen!", "Yes, I know it's wood. Get over it!" (TV: The Doctor, the Widow and the Wardrobe) Oddly, he defended once, "Oi! Don't diss the sonic!" (TV: The Hungry Earth) At some point it had an anti-freeze setting. (TV: The Snowmen)

It was destroyed and replaced repeatedly: bitten in half by a sky shark and left behind, (TV: A Christmas Carol) given to the Ganger Doctor, (TV: The Rebel Flesh) or simply fried out from over usage. In the latter instance, a replacement was given to him by Santa Claus. (COMIC: Silent Knight)

Security

 * Trying (unsuccessfully) to open the exit back into Starship UK. (TV: The Beast Below)
 * Opening the chest plate of an android's controls. (TV: Victory of the Daleks)
 * Opening the entrance hatch of a space ship. (TV: Flesh and Stone)
 * Breaking open padlocks. (TV: The Hungry Earth)
 * Locking the TARDIS doors. (TV: Cold Blood, The Doctor's Wife)
 * Opening the gate to the London Underground. (GAME: City of the Daleks)
 * Opening up a discarded Dalek dome. (GAME: City of the Daleks)
 * Bypassing Dalek security seals. (GAME: City of the Daleks)
 * Opening up control panels in Kaalann. (GAME: City of the Daleks)
 * Closing and locking a door to a Cyber-conversion room. (GAME: Blood of the Cybermen)
 * Unlocking Cyber-conversion unit manacles. (GAME: Blood of the Cybermen)
 * Opening an electronic door. (GAME: Shadows of the Vashta Nerada)
 * Opening the door to a time ship. (TV: The Lodger)
 * To open, close and lock the Pandorica. (TV: The Big Bang)
 * Unlocking the door to Melody's room. (TV: Day of the Moon)
 * Unlocking Amy's restraints. (TV: Day of the Moon)
 * Locking the TARDIS. (TV: The Doctor's Wife)
 * Unlocking a grating. (TV: The Almost People)
 * Locking a grating into place. (TV: The Almost People)
 * Closing doors inside a Cyber Ship. (TV: A Good Man Goes to War)
 * Opening doors on Demons Run. (TV: A Good Man Goes to War)
 * Opening a fake door. (TV: The God Complex)
 * Sealing the trapdoor that Gantok fell down, out of fear of the carniverous skulls. (TV: The Wedding of River Song)
 * Turning off the defence system of Kahler-Jex' ship. (TV: A Town Called Mercy)
 * Locking a door in the Great Intelligence Institute office. (TV: The Snowmen)
 * Stripping away the disguise around the Great Intelligence's voice. (TV: The Snowmen)
 * Unlocking the door of the Maitland home. (TV: The Bells of Saint John)
 * Unlocking the door of an aeroplane's cockpit. (TV: The Bells of Saint John)
 * Opening the secret entrance to the Doctor's tomb. (TV: The Name of the Doctor)

Medical

 * Forcing a star whale to regurgitate by overloading its chaemo-receptors. (TV: The Beast Below)
 * Simultaneously healing and analysing wounds. (TV: The Vampires of Venice)
 * Scanning lifeforms to determine how integrated into a host body they are. (TV: Amy's Choice)
 * Scanning piles of dust for traces of people. (TV: Amy's Choice)
 * Scanning an infection. (TV: Cold Blood)
 * On the right "prozatic setting", can stun any creature; however, because the Doctor couldn't see the Krafayis, he couldn't get the seting right and ended up pleasing the creature instead. (TV: Vincent and the Doctor)
 * Stunning the Silence. (TV: Day of the Moon)
 * Confirming how long Idris's body has before the TARDIS Matrix causes it to die. (TV: The Doctor's Wife)
 * Scanning the Flesh. (TV: The Rebel Flesh)
 * Detecting differences between Gangers and humans (TV: The Almost People)
 * Dissolving Gangers. (TV: The Almost People)
 * Detecting if a person was fatally wounded. (TV: A Good Man Goes to War)
 * Melting the Ice Governess using the new anti-freeze setting (TV: The Snowmen)
 * Trying but failing to melt the Ice Governess again once she came back. (TV: The Snowmen)
 * Stunning the Rutan Lady Winters. (GAME: The Gunpowder Plot)
 * Scanning the deceased to determine what caused death (later revealed to be the removal of faith) with no success. (TV; The God Complex)
 * Scanning for lifesigns. (TV: Closing Time)
 * Scanning pieces of what used to be the Ice Governess. (TV: The Snowmen)
 * Stripping away the disguise of the Great Intelligence. (TV: The Snowmen)
 * Stripping away the disguise of a Spoonhead. (TV: The Bells of Saint John)
 * Scanning the people in an aeroplane to find out that they were unconscious. (TV: The Bells of Saint John)

Diagnostic

 * Scanning Starship UK's engine room to determine that there was no actual engine powering the spaceship. (TV: The Beast Below)
 * Scanning voting booth for memory erasing function. (TV: The Beast Below)
 * Scanning Father Octavian's computer. (TV: The Time of Angels)
 * Determining the nature of the cracks throughout time and space; which was "extremely very not good." (TV: Flesh and Stone)
 * Scanning for heat signatures. (TV: Cold Blood)
 * Scanning Stonehenge. (TV: The Pandorica Opens)
 * Helping trace who received the Pandorica's summons. (TV: The Pandorica Opens)
 * Scanning the Pandorica. (TV: The Pandorica Opens)
 * Scanning with a parabolic satellite dish for an exploding TARDIS. (TV: The Big Bang)
 * Scanning a vortex manipulator to see if it was wired into something. (TV: The Big Bang)
 * Confirming the isomorphic nature of a control panel. (TV: A Christmas Carol)
 * Scanning boxes of stolen NASA equipment to confirm that they just what they look like. (TV: The Impossible Astronaut)
 * Scanning a spacesuit. (TV: Day of the Moon)
 * Confirming if a nanorecorder was on telepathic transmission or a replay. (TV: Day of the Moon)
 * Determining that the Siren used reflections to appear by scanning the hat of a pirate who was taken. (TV: The Curse of the Black Spot)
 * Confirming the nature of an alien life-support system. (TV: The Curse of the Black Spot)
 * Scanning for Hypercube transmissions to locate their source. (TV: The Doctor's Wife)
 * Scanning for monsters and how powerful they were. (TV: Night Terrors)
 * Scanning dimensional lesions. (GAME: The Gunpowder Plot)
 * Detecting electrical interference. (TV: Closing Time)
 * Confirming increased sulphur emissions. (TV: Closing Time)
 * Scanning a Dalek's database for information, specifically anything that his oldest enemies knew about the Silence. (TV: The Wedding of River Song)
 * Scanning a Headless Monk head box to confirm its contents. (TV: The Wedding of River Song)
 * Scanning Albert Einstein's liquid to determine if it was the ingredient he thought he needed to make a time machine. (TV: Death Is the Only Answer)
 * Scanning the lifeforce transference crown. (TV: The Doctor, the Widow and the Wardrobe)
 * Scanning a load of rocks and wood, determining that they were just that. (TV: A Town Called Mercy)
 * Scanning the electric lights in Mercy to determine how far advanced the technology was. (TV: A Town Called Mercy)
 * Scanning a Weeping Angel. (TV: The Angels Take Manhattan)
 * Scanning a frozen pond. (TV: The Snowmen)
 * Scanning the melted Ice Governess to make sure she was gone and draining through the carpet. (TV: The Snowmen)
 * Scanning a Cybermite. (TV: Nightmare in Silver)
 * Scanning the Doctor's time stream. (TV: The Name of the Doctor)
 * Detecting the progress of the War Doctor's calculation in his iteration of the sonic screwdriver. (TV: The Day of the Doctor)

Technology

 * Isolating the lighting so that the Weeping Angels could not drain the power. (TV: Flesh and Stone)
 * Redirecting all the power to the doors in order to open them. (TV: Flesh and Stone)
 * Detecting the location of lights. (TV: Amy's Choice)
 * Exploding lightbulbs. (TV: Amy's Choice)
 * Hacking into computer records. (TV: The Hungry Earth)
 * Activating bio-programmed soil. (TV: The Hungry Earth)
 * Accessing the Visualiser eye and repowering it. (GAME: City of the Daleks)
 * Tampering with the Dalek Emperor's casing. (GAME: City of the Daleks)
 * Activating a Dalek console trap. (GAME: City of the Daleks)
 * Constructing a Dalek Vision Disruptor. (GAME: City of the Daleks)
 * Fixing platform lift control panels. (GAME: Blood of the Cybermen)
 * Disassembling a Chronon Blocker. (GAME: TARDIS)
 * Activating emergency light switches. (GAME: Shadows of the Vashta Nerada)
 * Turning on the lights inside a generator. (GAME: Shadows of the Vashta Nerada)
 * Unsuccessfully attempting to free Sophie's hand from the time ship console. (TV: The Lodger)
 * Changing a hologram between its different forms. (TV: The Lodger)
 * To send a signal through to Amy's communicator to help guide her through a forest. (TV: Flesh and Stone)
 * Uploading proximity-alerting software to Amy's communicator. (TV: Flesh and Stone)
 * Disabling Silurian weapons. (TV: Cold Blood)
 * Scrambling a Cyberarm's circuits. (TV: The Pandorica Opens)
 * Giving orders to androids. (PROSE: The War of Art)
 * To reconfigure the binaries in the TARDIS. (GAME: Evacuation Earth)
 * Disabling a force field. (TV: A Good Man Goes to War)
 * Hailing the Eleventh Doctor's sonic cane. (TV: Let's Kill Hitler)
 * Disabling privileges from the Teselecta's crew. (TV: Let's Kill Hitler)
 * Activating George's toys. (TV: Night Terrors)
 * Detaching the view glass from the visitation facility. (TV: The Girl Who Waited)
 * Augmenting the view glass to work disconnected. (TV: The Girl Who Waited)
 * Locking on to Amy's timestream. (TV: The Girl Who Waited)
 * Switching off CCTV monitors. (TV: The God Complex)
 * Repairing and activating a lift. (TV: Closing Time)
 * Fusing the controls of a Cyberman teleporter. (TV: Closing Time)
 * Overloading/imploding a Cybermat; unfortunately wiping its memory in the process. (TV: Closing Time)
 * Repairing the controls of a Cyberman teleporter and using it. (TV: Closing Time)
 * Taking apart a Supreme Dalek. (TV: The Wedding of River Song)
 * Freezing the Teselecta in place; this caused sparks to fly inside of it. (TV: The Wedding of River Song)
 * Used to help with rewiring the TARDIS; he told Lilly it was because the light in his "wardrobe" wasn't working, claiming it was the reason he dressed as he did. (TV: The Doctor, the Widow and the Wardrobe)
 * Setting the TARDIS on its "adventure setting". (TV: Good as Gold)
 * Reversing a friction amper. (COMIC: The Cornucopia Caper )
 * Deleting an answering machine message from the phone the message was made from. (WC: Pond Life)
 * Activating the reverse in a badly damaged, insane Dalek's casing to send it into other insane Daleks (as it was going to self-destruct). (TV: Asylum of the Daleks)
 * Taking apart the device emitting the Silurian Ark's signal, and activating it upon placing it in Solomon's ship. (TV: Dinosaurs on a Spaceship)
 * Disabling the android the Shakri put on Earth to control the cubes. (TV: The Power of Three)
 * Reversing the Shakri's programming of the cubes to jump-start the hearts of the humans they previously stopped. (TV: The Power of Three)
 * Overloading a lightbulb, creating a blinding light, to act as a distraction to escape the Angels. (TV: The Angels Take Manhattan)
 * Getting rid of the shield that was blocking the Ice Governess and putting a new one behind the Doctor and Clara (TV: The Snowmen)
 * Seemingly adding an extra layer of super dense water vapour to keep the Ice Governess "trapped for the moment" (TV: The Snowmen)
 * Turning off the TARDIS anti-grav. (TV: The Name of the Doctor)
 * Activating the memory-erasing device in the Black Archive. (TV: The Day of the Doctor)

Amplification

 * Amplifying an electrical beam. (TV: The Beast Below)
 * To increase a signal's strength. (TV: The Time of Angels)
 * Making the voice of a star whale audible to the human ear. (TV: The Beast Below)
 * Displaying energy barricades which are usually invisible to the naked eye. (TV: The Hungry Earth)
 * Transmitting Abigail's singing from one broken segment to the other to open the cloud belt. (TV: A Christmas Carol)
 * Amplifying the sonic probe. (TV: The Girl Who Waited)
 * Creating a high pitched noise to get attention. (TV: The God Complex)
 * As a microphone. (TV: The God Complex)
 * Creating a sound loud enough to distract Kahler-Tek to allow the Doctor's escape. (TV: A Town Called Mercy)

Other

 * As a torch with blue light. (TV: The Beast Below)
 * Blocking out the effects of perception filters. (TV: The Vampires of Venice)
 * Giving a Cybermat a "Cyber-Migraine". (GAME: Blood of the Cybermen)
 * Distracting Cybermats. (GAME: Blood of the Cybermen)
 * Heating water and ice. (GAME: Blood of the Cybermen)
 * Lighting flaming torches. (TV: The Pandorica Opens)
 * Heating up a teapot. (PROSE: Snowfall)
 * As a lure to attract a Sky fish. (TV: A Christmas Carol)
 * Attempting self-reconstruction via signalling its other half; it failed at this and was left behind by the Doctor to be replaced by a similar sonic screwdriver. (TV: A Christmas Carol)
 * Protecting two versions of Rory Williams from falling victim to the Blinovitch Limitation Effect (PROSE: Touched by an Angel)
 * Damaging a Cyber Ship. (TV: A Good Man Goes to War)
 * Disarming Melody Pond. (TV: Let's Kill Hitler)
 * Igniting a cannon. (GAME: The Gunpowder Plot)
 * Destroying a Weeping Angel. (TV: Good as Gold)
 * Destroying the Star of Solitude. (COMIC: The Cornucopia Caper)
 * Holding a heavy door with an acoustic lock open in the pyramid of the rings of Akhaten. (TV: The Rings of Akhaten)
 * Holding back the Vigil. (TV: The Rings of Akhaten)
 * Tracking the location of Grand Marshall Skaldak as he sneaked around out of his armour. (TV: Cold War)
 * Receiving a signal from the TARDIS indicating that it had returned and indicating its location. (TV: Cold War)
 * Enhancing the power of an arsenal of bombs (TV: Cold War)
 * Relaxing the grip from someone's hand. (PROSE: Shroud of Sorrow)

River's screwdriver
The Doctor created another screwdriver before River Song's final date with him at the Darillium Singing Towers. This version of the sonic screwdriver had the settings of the Tenth Doctor's model when he met her at the Library along with "dampers" and a "red setting" that allowed it to work without interference from Doctor Moon. The Doctor gave it to River so she would be ready when she met his tenth incarnation in the Library. Unknown to her, this version included a Neural Relay which would save her data ghost for uploading into the main computer of the Library. (TV: Silence in the Library / Forest of the Dead)

Known uses

 * Activating and disabling gravity platforms. (TV: Forest of the Dead)
 * Slowing the descent of a fall. (TV: Forest of the Dead)
 * Fixing light bulbs. (TV: Forest of the Dead)
 * Storing the consciousness of an individual (specifically River's). (TV: Forest of the Dead)
 * Increasing mesh densities to over 800%. (TV: Forest of the Dead)

Related tools

 * A clone of the Second Doctor also possessed a sonic screwdriver, which he used along with the Fourth Doctor's to send Hexford home. (AUDIO: Survivors in Space)
 * Romana II constructed her own sonic screwdriver. Her version was so impressive, that the Doctor offered to swap sonic screwdrivers with her. (TV: The Horns of Nimon) She later gave it to the Doctor. (PROSE: Lungbarrow)
 * The Fifth Doctor had a device called a sonic prodder, although he didn't consider it a tool like "his beloved sonic screwdriver" (PROSE: Falling from Xi'an)


 * The Fifth Doctor also kept a Molenski Univarius in the TARDIS for repairs. He described it as a Gallifreyan "Swiss Army knife". While exploring the Axis, he carried it with him and used it in the same fashion as later models of the sonic screwdriver, even using the sonic properties to fend off creatures with sound waves before it ran out of power and was discarded. (AUDIO: The Axis of Insanity)


 * The Eighth Doctor, despite having lost his memories, built a device he called a sonic suitcase using eighties technology. (PROSE: Father Time)


 * had a similar tool, called a laser screwdriver. (TV: The Sound of Drums)


 * Captain Jack Harkness and later River Song had sonic blasters. (TV: The Empty Child / The Doctor Dances, Silence in the Library / Forest of the Dead)


 * Using stolen and incomplete UNIT design plans, Toshiko Sato created a sonic modulator. (TV: Fragments)


 * Miss Foster had a sonic pen with a design similar to the Tenth Doctor's sonic screwdriver. (TV: Partners in Crime)


 * The Doctor gave Sarah Jane Smith a sonic lipstick, a similar tool. (TV: Invasion of the Bane)


 * The Doctor mentioned that he once had a laser spanner as well, but Emmeline Pankhurst took it from him. (TV: Smith and Jones)


 * Mrs Wormwood was in possession of a ring called a phonic disruptor. (TV: Enemy of the Bane)


 * The Sixth Doctor defeated Cybermen using a sonic lance, similar in function to the sonic screwdriver. The Doctor used it as a weapon. (TV: Attack of the Cybermen)


 * The Eleventh Doctor used a sonic cane to contact Amy Pond and Rory Williams while they were miniaturised inside the Teselecta and to scan the Teselecta. (TV: Let's Kill Hitler)


 * While trapped on Apalapucia for thirty-six years, Amy Pond cobbled together a sonic screwdriver from various pieces of technology, although she insisted on calling it a "sonic probe". She later admitted it was a sonic screwdriver. (TV: The Girl Who Waited)


 * Jackson Lake carried what is likely the most primitive iteration of the sonic screwdriver. His version was a regular 19th century screwdriver, which he claimed was sonic by virtue of it making a sound when it was struck against a surface. (TV: The Next Doctor)
 * Gabriel created a similar device that was made out of guns. (PROSE: The Pirate Loop)

The sonic screwdriver prop

 * The sonic screwdriver was retired during the Fifth Doctor serial The Visitation, as it was felt that it had been overused. It was absent for the Sixth and Seventh Doctor's eras, except in the TV Movie, in which the Seventh Doctor used it to lock the Master's remains away. The Eighth Doctor recovered it at the end of the film. The tool was reintroduced with the Ninth Doctor and has become the show's most frequently used gadget besides the TARDIS itself. It has since appeared in many Seventh and Eighth Doctor audio adventures from Big Finish Productions.
 * For unexplained reasons, the Tenth Doctor's sonic screwdriver had a green casing in The Infinite Quest.
 * During early production of Series 1 (2005), the production crew decided to switch from their original prop to one based on the toy sonic screwdriver because the first prop was prone to falling apart. The production team secured moulds of the toy replica to make a more reliable prop for the next season.
 * There are two main versions of the Tenth Doctor's sonic screwdriver - one has a slide feature with button, and one which does not slide and has a fixed button. The two prop types varied each episode.

Concept art

 * Early conceptual art of the modern era sonic screwdriver feature a different "tube" section. Notes refer to "glowing organic circuitry" and a movable ball-joint on the emitter to allow use around corners and in tight spaces. Instead of the "glowing circuitry," the actual prop and toy reproductions featured a black "swivel" like a simple helix. When given a personal copy of the concept art, David Tennant himself commented on the lack of the swivelling emitter.
 * Another early piece of concept art, similar to a simple Bitmap drawing, reveals that the black "cap" at the reverse end of the sonic screwdriver was intended to be an opening set of "feet," allowing the sonic screwdriver to plug into a section of the TARDIS console. This feature was also dropped from the eventual prop model.
 * When the Doctor handles the screwdriver, the clinking noises produced (when he throws and catches it) are created by repeating the motions with a corkscrew, the handles of which bump against the casing to produce the required noise. These noises are dubbed over the footage.

Sonic screwdriver toy

 * A toy of the Eleventh Doctor's version was seen in "Light Echoes", an edition of "The Sky at Night" broadcast on BBC4 on Wednesday 5th October 2010. The screwdriver was (jokingly) used to scan a part of the LOFAR radio telescope, then under construction in Chilbolton, Hampshire, UK.
 * The Eleventh Doctor's sonic screwdriver toy has a total of four sound effects, two of which alternate with every other button press. The third is activated by pressing twice and holding on the third button push. The fourth is activated with three presses and a hold on the fourth push. However, in some models of the toy, over-use of the hidden sound effects causes the sound functions to eventually break, leaving only the LED functional.

The Visual Dictionary

 * According to the non-fiction source, REF: Doctor Who: The Visual Dictionary, which this wiki does not count as a valid source, the sonic screwdriver was a common and basic Time Lord device. If needed, a Time Lord could make one from scratch in very little time.

Attack of the Graske
In NOTDWU: Attack of the Graske, the Tenth Doctor appears to break the fourth wall by noting the player at home's been watching his adventures. Later, he points the sonic screwdriver at the television screen, transferring its powers to the player's digital remote control. This, along with having the player choose multiple endings to this game, disqualifies it as a valid source on this wiki.

Other matters

 * In the original script for The Eleventh Hour, the Doctor referred to his screwdriver as "Level 4000" technology.
 * Scientists at the University of Dundee invented a device which turns objects with ultrasonic waves, an invention which has been described as a real-world version of the Doctor's sonic screwdriver.
 * The Poldigon scientists the Seventh Doctor encountered on Celdor knew of Sonic screwdrivers, but not of The Doctor himself. This suggests they were at least partly a Gallifreyan invention and not entirely of the Doctor's creation. (AUDIO: The Doomsday Quatrain)