Water Hag Water Hag was a term human s used to describe an advanced race of alien creature native to the planet Strepto . Biology . Water Hags were humanoid in basic appearance . Their skin was emaciated and the colour of mud and their eyes were yellow with black slits for pupils . They had extremely wide mouths filled with sharp teeth , capable of easily biting the head off a dog . They had talons " as hard as iron " instead of fingernails , which were sharp enough to slice someone in half and even carve out solid rock . This killing method was a characteristic marker of a Water Hag killing . Despite their savage attitude , they were intelligent as ( and possibly even more than ) a human and the ones led by Sally Blackteeth were able to navigate the rift through unknown means . Water Hags weren ' t entirely animals , also having vegetable traits ( giving them weed - like hair and bark - like skin ) . Water Hags possessed many superhuman abilities , even from birth , that made them difficult to evade or kill . They could disguise themselves as human , had strength superior to a human ' s , were incredibly quick ( to the point where their motion became highly blurred to the human eye ) , could fly using a cloud of water , had the ability to breathe both underwater and on land and could possibly dissolve into water . ( PROSE : " Something in the Water " ) Life cycle . The Water Hags appeared to be a female - only species , and their only method of procreation was to infect humans with a virus of sorts . This " virus " acted in the oesophagus , where it caused the development of a foetus - like organism made of phlegm and vegetable matter . At this stage , the creature was called a " Homunculus " and until maturity it would incubate and grow in the throat . As the organism grew , the host would develop a cough , then become weaker and weaker . Eventually , the host would die , then briefly reanimate ( this could occur as much as 40 years after the death , depending on circumstances and preservation ) . At this point , the Homunculus would attempt to extract testosterone from the host in order to catalyse its growth . If it succeeded , it would burst forth from its host ' s throat . They could then reach maturity to Water Hag form within a day . However , if the Homunculus did not get the required amount of testosterone , then during the host ' s short spell of unconsciousness , the Homunculus would die and be vomited by the host , " stillborn " as it were . This meant that it was nigh on impossible for the homunculus to procreate inside a female human unless it injected with testosterone . Likewise , if the Homunculus chose a male host and that host was injected with a mix of oestrogen , emetic s and antibiotics , then the parasite would die and be thrown up . ( PROSE : " Something in the Water " ) History . In 2009 , Sally took the name " Saskia Harden " and faked a suicide . With her being brought to the hospital , it allowed her to infect more people . Torchwood began to investigate , but they too became infected . Sally and her children then attacked Torchwood itself , but they were able to hold them off . When Sally tried to escape through the Rift , Jack Harkness followed her and pulled her back , weakening her and allowing the rest of Torchwood to kill her . With her death in the Rift , the other Water Hags were destroyed . ( PROSE : " Something in the Water " )