Fear

Fear was an emotion.

Some beings could feed on fear, like the entity on Phobos (AUDIO: Phobos) and the Fearmonger. (AUDIO: The Fearmonger)

Arthur Linwood was the first victim of the Keller Machine in Stangmoor Prison, when it killed him by turning his fear of rats against him. His fear was so great that rat bites and scratches manifested on his face and neck. (TV: The Mind of Evil)

Permians hunted by inducing a state of fear in their minds of their prey, then consuming them, stripping the flesh from bone more efficiently than chewing could manage. (AUDIO: The Land of the Dead)

The Sixth Doctor listed vertigo with agoraphobia and xenophobia as fears which, when mixed together, would form "naked fear". (PROSE: The Ultimate Evil)

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 balloons. (TV: The God Complex)