A bunch; giant fruit bat, silver fox, barn owl, Eurasian eagle owl, clouded leopard, giant millipede, or giant sea louse. A headcrab or a Dead Space Lurker (i.e., tentacled zombie baby) would also be pretty awesome, but that goes without saying.
... Actually, you know what? Screw the Lurker; I want a damn Hive Mind. With one of those, I'd get all the Lurkers I want, anyway.
... Actually, you know what? Screw the Lurker; I want a damn Hive Mind. With one of those, I'd get all the Lurkers I want, anyway.