Fear Fear was an emotion . The Twelfth Doctor saw fear as a superpower . ( TV : " Listen " ) He told Bill Potts and Nardole that " Fear keeps you fast . Fast is good . " ( TV : " Oxygen " ) Due to the effects of adrenaline , ( TV : " Oxygen " ) " your heart is beating so hard , I can feel it through your hand s . There ' s so much blood and oxygen pumping through your brain , it ' s like rocket fuel . Right now , you could run faster and you could fight harder , you could jump higher than ever in your life . And you are so alert , it ' s like you can slow down time . " ( TV : " Listen " ) Such a feeling would result in faster breathing , as well , though that could lead to a faster death , in places where oxygen was in short supply . ( TV : " Oxygen " ) Clara Oswald expressed , to a young First Doctor , that " fear can make you faster and cleverer and stronger . [ . . . ] If you ' re very wise and very strong , fear doesn ' t have to make you cruel or cowardly . Fear can make you strong . " She concluded that fear was like a companion , a constant companion , bringing people together . In fact , " Fear makes companions of us all . " ( TV : " Listen " ) The Twelfth Doctor sometimes purposely scared his companions , in order to " max up " their adrenaline , and therefore their capability at solving and surviving a new situation . ( TV : " Oxygen " ) Carol Richmond believed that fear was a weakness that could keep one from taking action . She maintained that fear could make one violent , as well . ( TV : " Strangers in Space " ) The First Doctor explained that fear loosened one ' s mind , and made one more vulnerable to mind control . ( TV : " The Unwilling Warriors " ) According to Miss Quill , the " first fear " was a fear that " everyone " went back to and could not face . The Lorr Ballon claimed that this was just cowardice . Quill claimed that a soldier without fear was inefficient , and was one that won battles , but lost wars . ( TV : " The Metaphysical Engine , or What Quill Did " ) Some beings could feed on fear , like the entity on Phobos ( AUDIO : " Phobos " ) and the Fearmonger . ( AUDIO : " The Fearmonger " ) The Keller Machine fed off the fears of its victims . They included Arthur Linwood , who was afraid of rat s ; Kettering , who was afraid of drowning ; the Third Doctor , who was afraid of fire ; Alcott , who was afraid of dragon s ; and , who was afraid of the Doctor . ( TV : " The Mind of Evil " ) Permian s hunted by inducing a state of fear in the minds of their prey . ( AUDIO : " The Land of the Dead " ) The First Doctor noted fear as an example of emotions to the Cyberman leader Krail , along with hate , pride and love . He questioned , " Have you no emotions , sir ? " ( TV : " The Tenth Planet " , " Twice Upon a Time " ) The Sixth Doctor listed vertigo with agoraphobia and xenophobia as fears which , when mixed together , would form " naked fear " . ( PROSE : " The Ultimate Evil " ) When facing Eknodine , the Eleventh Doctor remarked to Rory Williams that they were bent on killing them as fear turned them into savages . ( TV : " Amy ' s Choice " ) Confronting the Dalek s , the Ninth Doctor voiced his belief that , despite their purging of emotions , one little spark of fear remained in their DNA . He goaded to them that that spark of fear " burn [ ed ] " when they faced him . ( TV : " The Parting of the Ways " ) Addressing human kind shortly before the Battle of Canary Wharf , Cyber - Leader One assured the people of Earth that they need not fear as the emotion would be removed upon their conversion into Cybermen . ( TV : " Doomsday " ) George psychically deposited all his fears in his doll ' s house , which manifested as peg dolls . ( TV : " Night Terrors " ) On the Minotaur ' s prison ship were pictures of those who had fed it and what their fear was . They included Novice Prin , who was afraid of sabrewolves ; Lady Silver Tear , who was afraid of Daleks ; Royston Luke Gold , who was afraid of Plymouth ; Tim Heath , who was afraid of having his picture taken and Tim Nelson , who was afraid of balloon s . ( TV : " The God Complex " ) The Seventh Doctor regarded fear as a self - preservation mechanism . ( AUDIO : " Harvest of the Sycorax " ) The Eleventh Doctor thought that anyone who wasn ' t scared of a Weeping Angel was a moron . ( TV : " The Time of Angels " )