Eight Legs The Eight Legs were a race of giant spider s with psychic power s . Characteristics . Physical characteristics . The Eight Legs were black spider s , 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 spider s 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 " ) 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 " ) 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 " )