Phobovore

The Phobovores were small grey humanoids from another dimension with long noses and in their own right dull rather than scary. They fed on fear – fear generated in others, and only with that fear could they exist in our dimension. They used a 'Ghost Train' ride at a fair as a means of scaring people who they then kidnapped for a few days by hooking them up to a machine that created nightmares for them while they fed. The hosts were released unharmed a few days later with no memory of the recent events that had occurred. Rory Williams was not a good choice of fear provider because his faith in the Doctor and Amy Pond helped him overcome his fears and the Phobovores were left weakened and forced to return to their own dimension. (DWA: Ghost Train)