Hoothi The Hoothi ( pronounced " Hoot - eye " ) were fungoid creatures , described by the Seventh Doctor as the " the master strategists of the galaxy " . Biology . Hoothi creatures were masses of grey with bulbous heads and tendrils . They fed on blood and breathed gases poisonous to human s . Depending on how strong they were , a single Hoothi could only control a single slave . The Hoothi were a group mind , usually travelling in fours that formed their own group minds within the greater Hoothi Consciousness . They could also access the memories and experiences of the beings they brought into the group mind , and it was possible for an absorbed being to regain their individuality and affect the rest of the group mind . A single Hoothi could still retain the millions of individuals that had been absorbed . Their infestation spread through spores resembling white fibres that could enter various lifeforms , usually working better with more complex nervous system s . Infected beings could be identified by their retinal patterns , and the spores could be activated at any time , causing an infected creature to explode with grey fibres until fully absorbed . Creatures absorbed by the Hoothi included a Time Lord , humans , Heavenite s , and a Terileptil . ( PROSE : " Love and War " ) Technology . Hoothi travelled in silent gas dirigibles that were able to hide within hyperspace . These ships , constructed from animal bones and tissue , were usually crewed by four Hoothi holding psychic control over their slaves . The ships were undetectable because of the Hoothi ' s psychic powers . Bubbles could form inside a sphere to give visitors a breathable atmosphere . A staircase could descend from these ships to allow for boarding , and they were also able to enter Puterspace . ( PROSE : " Love and War " , AUDIO : " Love and War " ) History . While the Earth was still forming , Gallifrey did business with the Hoothi . It was unclear to the Seventh Doctor if they evolved or were artificially created . Some said that they evolved on a world where the climate changes wiped out all other life , described by the Doctor as growing up with death . They lived off decayed matter , infesting bodies and using them as pawns in a game . Hoothi spores had spread throughout time and space , even reaching 20th century Earth . The Time Lord s tried negotiating with one world , but the Hoothi attacked them . The Time Lords sent an ambassador to the Hoothi worlds , but the Hoothi used him as a host . They attacked Gallifrey , but the Time Lords fought back and won with their advanced biochemistry . Before the Hoothi worlds could be time looped , the creatures had fled the Mutter ' s Spiral . At some point , they returned , using Heaven as a place to grow corpses , even manipulating the soil so that the bodies preserved better , waiting millions of years to begin a new attack against the Time Lords . They collected the Heavenite s in cycles , eventually " recycling " all of the animal matter of the Heavenites . They eventually manipulated data so that Heaven became a graveyard for those that died in wars and controlled the Vacuum Church as pawns in their plan . In 2570 , the Hoothi awoke the dead . Through the manipulation of the Seventh Doctor , Jan Rydd used his pyrokinesis to set the Hoothi sphere that was over Heaven alight , killing three of the four Hoothi . Ace spoke to the part of the group mind containing her friend , Julian Milton , causing it to die . ( PROSE : " Love and War " ) Other references . Maren of the Sisterhood of Karn claimed that no ship could approach Karn without the Sisterhood knowing , saying that even the silent gas dirigibles of the Hoothi were felt in their bones . ( TV : " The Brain of Morbius " ) Upon seeing a toy Dalek in a child ' s toybox , Benny mused that there could have been a fluffy Hoothi in amongst the toys also . ( PROSE : " Sleepy " )