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The Raxacoricofallapatorians were a race from the planet Raxacoricofallapatorius.


External features[]

Raxacoricofallapatorians were large, bulky humanoids. They had large eyes and powerful arms with long claws. They had thick, lumpy skin, ranging in colour from a yellowish green, (TV: Aliens of London/World War Three/Boom Town) a paler, grey-green, (PROSE: The Monsters Inside) a much darker shade of green, (TV: The Nightmare Man) a brownish orange, (TV: The Gift) blue, (COMIC: Doctormania) or maroon. (AUDIO: The Taste of Death)

Raxacoricofallapatorians hatched from large, green eggs with several tendrils. (TV: Boom Town) By the age of twelve, Raxacoricofallapatorians were still considered children and were shorter than a human of equivalent age. (TV: Revenge of the Slitheen) As Raxacoricofallapatorians aged, they lost moisture from their tissue, calcifying and effectively turning into stone. (PROSE: The Slitheen Excursion)

Despite their large bulk, they were also capable of surprising speeds and could easily overpower a human. (TV: Aliens of London / World War Three) One female was seen to behead a stone Weeping Angel with a single swipe of her claw. (COMIC: A Confusion of Angels)

Supposedly, Raxacoricofallapatorians were impervious to bullets, with one boasting that they would bounce off her hide. (AUDIO: Death on the Mile)

Raxacoricofallapatorians could hunt by scent and could identify an individual's species, age, sex, emotional state and location by it. (TV: Aliens of London / World War Three) This sense of smell was officially the best in the galaxy. (TV: Revenge of the Slitheen) They could also sense the pain of closely related individuals from far away. (TV: Aliens of London / World War Three)

Internal anatomy[]

Raxacoricofallapatorians were largely calcium-based life forms, specifically made of living calcium phosphate (TV: World War Three), although in one account they were described as silicon-based. (PROSE: The Slitheen Excursion) Despite this, when posing as humans, they were able to eat carbon-based food, with some even enjoying it. (TV: The Gift) Due to their biochemistry, Raxacoricofallapatorians were vulnerable to acetic acid and would react explosively to it, (TV: World War Three) a feature that was utilised in the Raxacoricofallapatorian death penalty. (TV: Boom Town)

Raxacoricofallapatorians had a more efficient metabolism than a human, meaning they only needed to eat every few weeks and produced less waste. Raxacoricofallapatorian blood was red and their tears were milky in colour and slightly acidic. (PROSE: The Monsters Inside) The females of the species could create poison when in danger, released either by a dart-like claw or through their breath. (TV: Boom Town) This breath could render a human unconscious. (COMIC: Doctormania)

Raxacoricofallapatorians had varying digestive systems according to family: A Slitheen noted the Hazrateen to have superior tastes which allowed them to enjoy the richest of foods, while the Blathereen were content with lower grade products. (AUDIO: The Taste of Death)

Raxacoricofallapatorians lived in the chalky hills and the tall tree forests of Raxacoricofallapatorius. They froze and calcified on ice planets. (GAME: Plant and Animal Habitats) There were also at least two oceans on the planet, in which the Raxacoricofallapatorians swam. (WC: Alien File: Blathereen)


The Slitheen and other criminals from the same race were scavengers, known for stealing advanced technology from other species. (TV: Revenge of the Slitheen) They were more advanced than humans and had developed faster-than-light travel in the form of slipstream engines sometime prior to 2006. They could also modify a pig into a humanoid form using their own technology. (TV: Aliens of London / World War Three) They also had small, hand-held teleportation devices, though they tended to have limited range and capabilities. (TV: Boom Town, TV: The Gift) Some of the Raxacoricofallapatorian technology appeared organic in nature. While in Justicia, Ecktosa and Dram used sticky nets as hammocks. These nettings were covered in a slime that quickly hardened away from body heat. Other Raxacoricofallapatorian buildings had their floors covered in a sticky substance. (PROSE: The Monsters Inside) In the 347th century, the Raxacoricofallapatorians also had molecular repurposing devices. (PROSE: The Slitheen Excursion)

A Slitheen spaceship. (TV: Aliens of London)

The Raxacoricofallapatorians' most distinguishable technology was their compression fields. The Slitheen (TV: Aliens of London / World War Three) and Blathereen families (PROSE: The Monsters Inside) were able to disguise themselves as other, smaller humanoids by fitting into their skins. This was done with the compression-field collars that they wore on their necks. When unzipped, pent-up energy was released through the zip in the form of a flickering blue light. Their size was controlled by the movement of gas, which caused a condition similar to farting, but with a smell slightly similar to that of bad breath due to calcium decay. (TV: Aliens of London / World War Three) These individuals originally needed to be large, but the advancement of technology meant smaller skins could be used. (TV: The Lost Boy, PROSE: The Monsters Inside) These skin suits were apparently inferior to those of other species. (PROSE: The Nightmare of Black Island)

The Raxacoricofallapatorians mastered the concept of string theory. (TV: Revenge of the Slitheen)


A young member of the Slitheen family. (TV: Revenge of the Slitheen)

According to Blon Fel-Fotch Passameer-Day Slitheen, "family [was] everything" to Raxacoricofallapatorian culture. (AUDIO: Sync) Their society centred around several major families, including the Slitheen, Blathereen, Slavereen, Caizeen, Lilieen, Rackateen, Chippeen, Fittereen, Hanazeen, Glizeen, Hostrozeen and Arlene. Raxacoricofallapatorian names were complex with the various hyphenation showing their exact placement on the family lines. (WC: Monster File: Slitheen) There were also mixed families, such as the Slitheen-Blathereen family (TV: The Gift) or the Hanazeen-Blathereen family. (PROSE: A Comedy of Terrors)

Raxacoricofallapatorians were led by a Grand Council and an Assembly. (TV: Revenge of the Slitheen) The leader of this Council was the Lord Predator. (PROSE: The Slitheen Excursion)

Unlike the Slitheen and Blathereen families, most Raxacoricofallapatorians were a peaceful race that taught their children maths and poetry. They made their home world a paradise for them and other peace loving species and some of them were brilliant farmers but they despised criminal members of their species and punished them without mercy.

The Raxacoricofallapatorians had the death sentence, in effect as late as the 2000s, for dangerous criminals like the Slitheen, which was carried out in a gruesome way. The criminal would be lowered into a cauldron of acetic acid, which would then be heated to boiling. The acidity of the solution was formulated to dissolve the skin, allowing the internal organs to drop into the liquid "soup" while the condemned was still alive, resulting in a slow and painful death. (TV: Boom Town) At some point, however, this sentence was lifted, with captured Slitheen instead being taken into incarceration. (AUDIO: The Taste of Death)

Two Slitheen-Blathereen in their ship. (TV: The Gift)

Based on the comments of Blon, Raxacoricofallapatorians neither brushed their teeth nor prepared their food in complicated ways. (TV: Boom Town)

Two known Raxacoricofallapatorians insults were "May plaque brown your belly" and "May your mother boil in the cauldron of atonement". Both were presumably related to their calcium based biology. (PROSE: The Monsters Inside)


Raxacoricofallapatorians were part of the four-world Raxas Alliance along with the Abzorbalovians and the people of Raxacoricovarlonpatorius and Clix. (TV: The Gift)

Sometime before the 21st century the criminal Slitheen family bribed their way into power on Raxacoricofallapatorius. Their rule crashed the planet's economy and eventually the population rose up against them. (TV: The Gift) Exposed, shamed, and arrested, the entire family was tried and found guilty with no chance of appeal and given the death sentence. Many of the Slitheen fled justice, but the family continued to be hunted down by the Blathereen family and Judoon. (TV: Revenge of the Slitheen)

The Cybermen on Raxacoricofallapatorius. (COMIC: Assimilation²)

Branded as criminals, and fleeing Raxacoricofallapatorius on pain of gruesome capital punishment; (TV: Boom Town) the Slitheen engaged in a variety of illegal schemes across the galaxy, including on Earth, where they came across the Doctor (TV: Aliens of London, World War Three, etc.) and Sarah Jane Smith. (TV: Revenge of the Slitheen, From Raxacoricofallapatorius with Love) The actions of the Slitheen "ruined the good name" of the Raxacoricofallapatorians. (TV: Revenge of the Slitheen)

On 19 May 2311, the Raxacoricofallapatorians annexed the planet Tivoli, wiping out the Stenza occupation force that controlled it at the time. They were collectively arrested for this "crime" by the Judoon on 14 June 2426, ending their stewardship of Tivoli, which ultimately fell under the control of the Kraal instead. (PROSE: Time Traveller's Diary)

In the 347th century, Raxacoricofallapatorians (possibly just the Slitheen) fought in the Platonic War, alongside various other alien races, against the human race.

In the year 34,600, the Lord Predator was Haralto Wong Bopz Wim-Waldon Arlene. However he died shortly after this. (PROSE: The Slitheen Excursion)

Alternate timeline[]

In an alternate timeline the Cybermen, using Borg technology conquered Raxacoricofallapatorius and converted the entire populace into Cybermen. (COMIC: Assimilation²)

In a timeline created by a continuity bomb where the Doctor embraced the title of "Time Lord Victorious" and became a mad tyrant who ruled over time and space, a Raxacoricofallapatorian shot him dead without regeneration. (COMIC: Four Doctors)

Minor references[]

Rose Tyler remarked the Abzorbaloff was "a bit Slitheen", but when the Doctor asked he revealed that he was from Clom, Raxacoricofallapatorius' twin planet. The Abzorbaloff spoke of the Raxacoricofallapatorians with contempt. (TV: Love & Monsters)

The Tenth Doctor, having assumed the identity of John Smith, drew a picture of the Slitheen in A Journal of Impossible Things. (TV: Human Nature)

A Raxacoricofallapatorian was seen at the Zaggit Zagoo bar where the Tenth Doctor went to visit Jack Harkness one last time before his regeneration. (TV: The End of Time)

In 1903, after receiving a wealth of information from the future, Grigori Rasputin foresaw, among other things, creatures made of calcium. (AUDIO: The Wanderer)

Behind the scenes[]

A Raxacoricofallapatorian?

  • In COMIC: Four Doctors an alternate universe Tenth Doctor was killed by an alien that resembled a Raxacoricofallapatorian. However, it had hands with five digits and fingernails instead of the normal three clawed fingers.

Abandoned plans[]

The Visual Dictionary[]

The non-narrative source Doctor Who: The Visual Dictionary gave further information about Raxacoricofallapatorian biology and culture. It said they were well adapted to their home-planet, with large eyes to see through the blizzards of the poles and powerful arms to swim through the oceans and to hatch from their eggs. While hunting, they would use their strength and poison-tipped claws to kill their prey.