Eight Legs

The Eight Legs were a race of giant spiders with psychic powers.

Physical characteristics
The Eight Legs were black spiders, generally less than a metre in length, though the Great One was much larger. They relied on human mounts for transport, though they could scuttle along at walking pace. The Eight Legs could create webs like the spiders of Earth, though they were not sticky, merely tough. They fed on the flesh of living creatures, generally the sheep of Metebelis III, though they preferred human meat. (TV: Planet of the Spiders) They had twelve eyes. (PROSE: The Secret in Vault 13)

Powers and abilities
The Eight Legs could communicate through telepathy, discharge psychic energy, use mind control on humans, and teleport through both time and space. To teleport greater distances required more spiders to focus their wills.

They could ride on the backs of humans, turn invisible and possess the human who could act as a vessel for the Eight Leg's power. They could project psychic energy blasts, the strength of which varied according to the strength of the victim. (TV: Planet of the Spiders)

The Eighth Doctor said that the Eight Legs were one of the most highly developed species in psychic power. (AUDIO: Worldwide Web)

History
A starship of human colonists crash-landed on Metebelis III with Earth spiders on board. In the mountains, the native blue crystals caused the spiders to grow in size and mental power. Over the course of 433 Earth years, the spiders enslaved the colonists, forced them to harvest food and ate the humans themselves. They forbade the humans to use the word "spider" as it reminded them of their Earth origins, referring to themselves as "Eight Legs", and calling the humans "Two Legs". The Eight Legs developed a matriarchal society centred around the physically enormous Great One.

The Eight Legs planned to conquer the rest of the universe with the Great One planning to collect all of the blue crystals, believing it would give her immense powers. Though they were nearly successful, the final crystal was held by the Third Doctor on Earth. The Eight Legs sent an expedition back in time to obtain the final crystal. Though the crystal was returned to them, the power of the crystal web was too much to contain. The energy feedback destroyed the Great One. (TV: Planet of the Spiders)

Some Eight Legs survived the Great One's death and were hunted. One captured the Seventh Doctor and planned to eat him, but he was freed by the Eighth Doctor, who killed the spider with the Tissue Compression Eliminator. (PROSE: The Eight Doctors)

Some of the Eight Legs escaped to Earth by travelling down the ley lines. The Fourth Doctor and Romana II encountered the Eight Legs living in an isolated house in High Wycombe, hiding away and supplying food for their queen, while she gave birth to dozens of unhatched Eight Legs to take over the world.

The Doctor stopped the Eight Legs' plans by setting fire to the house, alerting the fire brigade. As the eggs began to hatch, the Doctor used the high powered jet of water from the houses to kill all the Eight Legs in the house. (PROSE: Return of the Spiders)

Iris Wildthyme encountered Giant Spiders on Metebelis III with her companion Timmy. (PROSE: The Scarlet Empress)

The Eight Legs hired the Headhunter to leave several Metebelis crystals in Yorkshire, which were subsequently found by Clark Goodman. The Eight Legs used Goodman to set up the Eightfold Truth, where he gathered followers for them. The Eight Legs then travelled across the astral plane and possessed the members of the group. (AUDIO: The Eight Truths) Using the technology left by the Headhunter for them, they used a Time Lord stellar manipulator to take over the minds of every being in the universe. They were stopped by the Headhunter, who hypnotised the Great One with her own message. The Eighth Doctor then sent a message out for all those possessed by the Eight Legs to forget them, sending the spiders back to their homeworld. (AUDIO: Worldwide Web)

In the War in Heaven
During the War in Heaven, history was rewritten by Faction Paradox so that the Third Doctor was killed on Dust prior to his encounter with the Eight Legs. (PROSE: Interference - Book Two) The Doctor's later incarnations never stopped the Eight Legs' plan for universal domination. (PROSE: The Blue Angel, The Ancestor Cell) The Enemy shared a connection with the Eight Legs. (PROSE: The Ancestor Cell, The Map and the Spiders, et al.)

Giant spiders made of bone swarmed the corridors of the Edifice, guarding a temporal ghost of the Third Doctor from the timeline where he died fighting the Eight Legs. (PROSE: The Ancestor Cell) Therapy filters applied to War-time agents of the Great Houses recovering from OMEGA level events deleted terminology relating to spiders. (PROSE: Subjective Interlock, The Short Briefing Sergeant's Tale, Timeshare, A Choice of Houses, No Enemy But Despair) The Infancy Gospel of Grandfather Paradox included a dialogue wherein the Grandfather suggested that spiders could be a good enemy of the Great Houses. (PROSE: Pre-narrative Briefings) Jezebella saw the corpse of a giant arachnid in the timeship of the Vermis Superior. (PROSE: Life-Cycle) A Thaumoctopus memeticus took the form of a spider while on the Greenworld. (PROSE: T.memeticus: A Morphology)

The 1880s, a crucial War nexus, saw a sudden increase in the use of the word "spider" in Earth literature. An Enemy representative in this decade exposed X-12 (PROSE: Pre-narrative Briefing S) to a Wilhelm Liebnecht story about an ambitious king becoming a puppet to a legion of spiders, a metaphor for the Great Houses being overthrown from within by the Enemy. (PROSE: The Map and the Spiders)

As part of what he believed to be the end of the War, the Eighth Doctor used the Edifice to restore pre-War history so that the Third Doctor once again sacrificed himself to defeat the Eight Legs. (PROSE: The Ancestor Cell)

Copies of the Eight Legs
While facing Jared Khan inside the mental plane of the Doctor's TARDIS, Bernice Summerfield encountered a mental representation of an Eight Leg. (PROSE: Birthright)

When Es'Cartrss tried to take over the Tenth Doctor's mind via the TARDIS' Matrix, he used his memories of the Eight Legs to attack him. (COMIC: The Forgotten)

Behind the scenes

 * In The Book of the Enemy, the allusions to spiders being the Great Houses' enemy are a reference not only to Eight Legs but also to 's Hugo Award-winning novel, which tells of a cosmic time war between the "Snakes" and the "Spiders".