The Flood ( The Waters of Mars ) The Flood was a viral species which originated inside a glacier on the planet Mars . The Flood needed a physical form to take on , so they infected a number of crew members from Bowie Base One , starting with Andrew Stone . It went on further , with the part of The Flood in Andy infecting Margaret Cain and Tarak Ital . After infecting Ed Gold , Steffi Ehrlich , and Roman Groom , Maggie went to break the glacier , but failed due to Adelaide Brooke initiating Action Five . Biology . The Flood ' s natural state was in liquid water . It was capable of controlling the water , causing it to flow in unnatural directions . It was also capable of infecting other life forms by coming into contact with them , making them spasm and convulse as they were taken over , mainly because it was a viral life - form . Once infected , the individual constantly exuded water , pouring from the body ; hands and mouth . This could be increased to produce high - pressure sprays from both the hands and the mouth . The infected victims would no longer draw their oxygen from air , but from water and they would be near walking corpses , as the infection greatly weakened their heartbeats and pulse . Also , the infection would cause a lot of electrical activity in the host ' s brain . Upon mutation , infected victims could deactivate nearby cameras . When infected , the hosts would also develop cracked skin ( especially around the mouth and neck ) and blackened teeth , as well as an internal fission in the host ' s body that produced the water . Some hosts , though not all , could develop faded blue eyes . The Tenth Doctor suggested that this might mean they were closer to human than those with the faded blue eyes . These physical symptoms could be masked , meaning that the infection could hide inside a human host , and infect him or her at any moment . The host also had the ability to survive on the surface of Mars . Hosts could also run extremely fast , even going as far as to keep up with a rocket - powered robot and outrun other running people . A single droplet of the viral water emitted by the host could pass on the infection to another host . Despite the considerable amount of water produced by the infection , the infected did not seem to be overly affected by electricity ( which salty water conducts well ) ; The infected Andy Stone was electrocuted by the Tenth Doctor , but was only momentarily incapacitated . However , the Flood creatures , being made almost entirely up of water and constantly producing it , could be destroyed by intensive heat . This weakness was shared with those most likely to have imprisoned them , the Ice Warriors . The Flood proved capable of coordinated action despite being scattered , as well as considerable intelligence . It could not communicate verbally once infection manifested itself , although victims could understand Ancient North Martian . Victims could no longer speak English , but could emit gurgling growls and snarls . The infected could also emit terrifying high - pitched screams that sounded like tortured metal , capable of cracking open ice , and communicating with other infected victims . Strangely , a victims ' scream could be heard through the thickest of metals . ( TV : " The Waters of Mars " ) History . At some point , the Flood was sealed inside a glacier in the Gustav Crater on Mars . The Tenth Doctor speculated it was by the Ice Warrior s . In 2058 and 2059 , the human colony Bowie Base One used the glacier as a water source . Original timeline . On 21 November 2059 , the Flood managed to infect Andy Stone when he ate a carrot he had washed thanks to a broken filter and the replacements not fitting , let them through into the water supply . The Flood proceeded to overrun Bowie Base One which eventually led to Captain Adelaide Brooke initiating Action Five . The resulting nuclear detonation destroyed Bowie Base One , the surviving crew , the infected personnel and the Flood . Many on Earth mourned the crew ' s death , but remained unaware of why Adelaide had destroyed Bowie Base One or that it was to stop the Flood from reaching Earth . ( TV : " The Waters of Mars " ) New timeline . In the altered timeline , the Tenth Doctor visited Bowie Base One at the same time that the Flood infected Andy Stone thanks to a broken filter . Reluctantly aided by the Doctor , the crew attempted to battle the Flood . The Flood learned of the abundance of water on Earth through the infected Margaret Cain and expressed a desire to reach Earth in order to spread . As the situation worsened , the Flood - infected Margaret , Andy , Steffi Ehrlich , Roman Groom and Tarak Ital started shattering the ice holding the rest of the Flood in order to release it . Though the Doctor originally refused to help as the destruction of Bowie Base One was a fixed point in time , he declared himself the Time Lord Victorious and attempted to save Adelaide , Mia Bennett and Yuri Kerenski . With the help of Gadget , the Doctor managed to transport the survivors to safety in his TARDIS . Before departure , Adelaide initiated Action Five which activated a nuclear device under Bowie Base One . The resulting nuclear blast destroyed Bowie Base One , the infected crewmembers and the Flood . Following Adelaide ' s suicide on Earth to correct the timeline , Mia and Yuri spread the story of the Flood infection of Bowie Base One and Adelaide ' s heroic actions to stop them . This inspired Susie Fontana Brooke to lead humanity into the stars . ( TV : " The Waters of Mars " )