Metebelis III Metebelis III was a famous blue planet in the Acteon Galaxy . The Third Doctor had attempted to reach Metebelis III several times during his tenure as UNIT ' s scientific advisor on 20th century Earth , finally succeeding and meeting some of the dangerous native wildlife . His interaction with radioactive material there triggered his regeneration . Astronomical data . The Doctor said Metebelis III was located in the Acteon Group . ( TV : " Carnival of Monsters " ) The blue moon of Metebelis III gave the whole planet a blue tint at night . It had many different habitats , including desert plains , green forests and mountain ranges . Native species included a giant snake , a species of giant bird and an intelligent , if primitive , species . ( TV : " The Green Death " ) It was later colonised by human s . ( TV : " Planet of the Spiders " ) The blue crystals of Metebelis III could break hypnotic spells and mind control . The Doctor used the crystal to break the hypnosis of the computer called BOSS . ( TV : " The Green Death " ) They could also enhance intelligence and psychic power s . Another type of stone on the planet could counteract the energy produced by the blue crystals . ( TV : " Planet of the Spiders " ) History . The Doctor attempted to visit Metebelis III a number of times , including once with Jo Grant , on his first trip with the TARDIS after his exile was lifted . He later visited the world at an unknown time period , when he deliberately wired the TARDIS coordinate programmer to go to the planet , stole a crystal and was attacked by wildlife . ( TV : " The Green Death " ) At some time in the planet ' s far future , a human starship crash landed there . Humans and sheep survived the trip , as did some spider s . In four hundred and thirty three years , the crystals mutated the spiders into larger , sentient creatures that called themselves the Eight Legs . They enslaved the humans , harvesting and devouring them like livestock , and disliking their Earth origins , decreed the word " spider " as forbidden . The Eight Legs planned to take over the rest of the universe , but required all of the blue crystals . The Doctor ' s theft of one of the crystals caused the ruler of the Eight Legs , the Great One , to send her minions to Earth to retrieve it . The series of events which followed led to the replacement of the crystal , which flooded the body of the Doctor and the Great One with radiation . This caused the death of the Great One and the regeneration of the Doctor into his fourth incarnation . ( TV : " Planet of the Spiders " ) Iris Wildthyme encountered the Eight Legs on the planet with her companion Timmy . However , Wildthyme had a habit of claiming the Doctor ' s adventures happened to her so the truth of this is unclear . ( PROSE : " The Scarlet Empress " ) The Sixth Doctor and Jason once visited Metebelis III , which was nowhere near as peaceful as the Doctor had been led Jason to believe . Jason later warned Crystal that she was never to allow the Doctor to take her to the planet . ( AUDIO : " Beyond the Ultimate Adventure " ) Feeling slightly depressed , the Seventh Doctor revisited Metebelis III to try to revive his spirits , hoping the beauty of the planet would give him something to appreciate and the danger would revive his interest in life . This goal was almost too successful when he was captured and nearly eaten by one of the surviving Eight Legs , but he was saved by his next incarnation as he paid a brief visit to his previous self . The Eighth Doctor used the Tissue Compression Eliminator he had recently stolen from the Master to kill the Eight Legs before it could eat them both . ( PROSE : " The Eight Doctors " ) The Eighth Doctor travelled to Metebelis III with Bazima . ( PROSE : " Transmission Ends " ) During their intergalactic pub crawl , the Eleventh Doctor , Strax , and Rory Williams visited the Blue Moon Tavern on Metebelis III and drank Lotus Gloom . Rory was shocked to discover that the drink was not consumed through the mouth , but by standing in a bowl of the drink . ( COMIC : " Time Gentlemen , Please ! " ) Other references . Bernice Summerfield once visited a bar on Metebelis III . ( PROSE : " Blood Harvest " ) During an encounter with Faction Paradox , the Doctor ' s history was changed so the Third Doctor regenerated on the planet Dust instead , which also saw him being infected with a Paradox biodata virus . The Eighth Doctor eventually learned the truth about the Faction ' s interference thanks to the interference of the TARDIS , allowing him to restore his original history and ensure the circumstances of his third incarnation ' s death occurred on Metebelis III . Before history was restored , the Doctor ' s TARDIS , corrupted into the Edifice as it attempted to contain the infection in itself to protect the Doctor , also manifested bone spiders as remnants of the timeline it was trying to restore , as well as the temporal ' ghost ' of the Third Doctor who should have existed before history was changed . ( PROSE : " Interference - Book One " , " Interference - Book Two " , " The Ancestor Cell " ) The Eleventh Doctor used a Metebelis crystal to boost the natural psychic abilities of Emma Grayling , in order to create and sustain a wormhole to a pocket universe and to rescue Hila Tacorien . ( TV : " Hide " ) Metebelis III was mentioned by Sarah Jane Smith just before her wedding , when she jokingly wondered where she would have sent the Doctor ' s invite . ( TV : " The Wedding of Sarah Jane Smith " ) Jo said to Sarah Jane that even if the Doctor died on somewhere as far as Metebelis III , she would feel it . ( TV : " Death of the Doctor " ) Metebelis crystals were sold at Primo Temp . ( COMIC : " Buying Time " ) The egg s on Metebelis III were blue . ( AUDIO : " The Man Who Wasn ' t There " ) Behind the scenes . In " Hide " , Matt Smith mispronounced the planet ' s name , saying " Meh - teb - alis " instead of " Met - a - bee - lis " .