Kraal android The androids produced by the Kraal s were utilised by Styggron as part of his plan to colonise the Earth . Through the use of a pattern analyser the memories and intelligence of the subject , as well as there appearance , were transferred to an android . History . Styggron had a replica of the village of Devesham and the nearby Space Defence Station created on the Kraal homeworld of Oseidon to function as a training ground for the androids . This continued for an extended period , despite Marshal Chedaki ' s criticism , as Styggron hoped to use the androids for further invasions after Earth was taken , so the techniques needed to be extensively tested . Guy Crayford , who had no duplicate , served Styggron as leader of androids based in the Defence Station . The village was populated with androids , matching the inhabitants of the real one . Other androids , service mechanic s , which wore white overalls and helmets with dark - tinted visors , patrolled the area . They were armed with weaponry fired from the index fingers of their right hands . Styggron produced a duplicate of a UNIT soldier programmed to become hostile to Kraals , against which he demonstrated the effectiveness of the weaponry he had developed , destroying it . The Fourth Doctor and Sarah Jane Smith found themselves in the Devesham replica while attempting to get to Earth . They found inconsistencies in the reproduction , such as coins that were all minted in the same year , phones that didn ' t work and a dartboard that had never been used . When Sarah attempted to converse with the locals in the Fleur - de - Lys , she was told by the android Adams that they didn ' t have strangers there . Sarah was captured by Styggron who produced an android replica of her . The Doctor quickly noticed the switch though as the real Sarah had lost her scarf while the android wore one . She displayed other uncharacteristic traits too , such as a taste for ginger beer , where her human counterpart " [ couldn ' t ] stand the stuff " . The real Sarah destroyed her android captor by using electricity with water as a conductor . An android duplicate of Harry Sullivan helped Styggron prepare the virus he intended to wipe out human ity with , unable to touch it himself due to the risk of contagion . The Kraals intended to use the androids to release the virus on Earth . Some were loaded into retro tube s , including a duplicate of the Doctor and one of Sarah . On Earth , several officials at the real Defence Station , including Colonel Faraday and John Benton had already been replaced with androids , their counterparts being aboard Crayford ' s XK - 5 space freighter where Styggron also was , hoping to be protected from the contagion . The Doctor , who uncovered the androids with his robot detector , had Grierson , a worker at the station , realign the radar dish es so that they pointed towards the base . The Doctor activated them , disabling the androids . Styggron was killed by his own virus . ( TV : " The Android Invasion " ) The skeleton of an inactive Kraal android was found in a prison ship that launched in 2000 BC . ( TV : " The Stones of Blood " ) SenéNet acquired one of the Kraal androids . ( PROSE : " Business Unusual " )