Talerian The Talerians were a race of aliens from the planet Taleria . Biology . Talerians were the same height as human s , but with grey - green skinned , blobby bodies covered in slimy pustules . Their heads were bulbous , with a slit - shaped mouth full of razor - sharp teeth , and a single , egg - shaped eye . They had no necks . Their skin was rubbery , able to deflect small impacts . More powerful attacks , such as a knife wound , or a change in atmospheric pressure , would rupture the skin , causing the Talerians ' liquid innards to gush out , killing them . With each passing generation , the Talerians grew more and more fragile . Technology . The Talerians wielded laser blasters capable of stunning or killing . They also wore armour to protect their frail bodies . History . Due to their increasingly fragile nature , the Talerians were a dying race . They grew desperate to find a new home with new bodies and one of them followed an unintentional signal from the mind - altering experiments of Professor Jackson at Base Diana on Earth ' s Moon . As the man was setting up his equipment for testing , the Talerian managed to enter his body and take over . The Talerian Jackson then began using Jackson ' s body and equipment to prepare for a Talerian invasion . He began using Jackson ' s equipment to erase the minds of the Base Diana personnel and replace them with Talerian minds that were being sent at intervals scheduled for Jackson ' s experiments so as not to draw attention . The Talerian also erased the minds of many of the other people and made them Blanks : humans who were controlled solely by programming with their real personalities shutting off at programed times . The Talerian Jackson kept backup copies of the minds of everyone he erased in the base ' s data storage and while he kept a copy of the real Jackson , he also kept the real Jackson ' s personality alive within his mind so he could use his knowledge to blend in perfectly . However , the real Jackson ' s mind began fading and was eventually barely even there anymore . By the time the Eleventh Doctor and Amy Pond arrived , most of Base Diana had been compromised by the Talerians . After the Doctor got trapped on Earth briefly , Amy learned the truth and got turned into a Blank . After Amy drank her backup which restored her mind , the Doctor fed the backups of every member of Base Diana into the base ' s fire suppression system and released the water with the help of Major Carlisle who was able to avoid being controlled by a Talerian due to a power failure at a crucial moment . The Talerian minds possessing the Base Diana personnel were destroyed and the original human minds regained control of their bodies . The Blanks were also restored to normal . However , the Talerian invasion was not thwarted as Jackson had kept his own backup on himself and the Talerian mind remained in control . Jackson called in a full Talerian invasion force to take Earth by force , but the Doctor managed to get his hands on Jackson ' s backup and slip it into his tea . The backup erased the Talerian mind controlling Jackson and restored the mind of the real Jackson . Remembering what he had done under Talerian control and what the Doctor had said about Talerian ' s being vulnerable to pressure change , Jackson shot out the huge glass window of his office , blowing himself into space . The pressure change through the base killed the Talerian invasion force and the Doctor and Amy were able to block the window and prevent anyone else from being harmed . The Doctor then dismantled Jackson ' s equipment to keep the Talerians from using it to return . ( PROSE : " Apollo 23 " )