Trevor "Doom" Buck Huntley, also known as simply Trevor or Doom, is a fictional, anthropomorphic black and brown dog, and the supposed younger brother of Rex. He is more of a joke character than anything and tends to make references to modern-day stuff that should not otherwise exist in whatever universe he's in.
Trevor is a black dog with brown ears, legs and underbelly, and a brown marking on his forehead which goes down between his eyes (similar to Rex). He has spiky blue hair, which is apparently natural (and he was born with it, too). Trevor has a tendency to wear WAY too much clothing. Trevor's most notable feature is his one large incisor which constantly sticks out, even when his mouth is shut.