Zombie

Zombies are re-animated humans. When a human is bit, they will eventually die, then re-animated and come 'back' to life. Zombies feast on warm flesh. Although they they not always rip off limps and eat them, they actually don't need to eat. The only semi-function part of a zombie is their brain. Zombies can have their arms and legs ripped off, and still function. The only thing they need IS their brains. You can only kill them but targeting their brains. You could use any object, but a gun would be preferred probably because I highly doubt anyone would actually want to be close enough to hit a zombie with bat or something. They one have one form, although there are many... zombies. What I mean is people have made them fast, slow, stupid, smart etc.