Crocodile

The Crocodile is a character from the Neverland world, and one of Captain Hook's enemies. He acquired a taste for the pirate captain when Peter Pan chopped off the captain's hand and fed it to him. He now follows Hook around everywhere, hoping to get a second taste of the captain. The crocodile isn't quite a villain, since he primarily hunts Captain Hook, but he does attack Sora and Ventus.

The crocodile swallowed a ticking alarm clock, that now, unfortunately for the crocodile, warns Captain Hook if he is approaching. This has become something of a trademark for the crocodile, foreshadowing its arrival in a way that terrifies the captain, much to his humiliation.

Kingdom Hearts Birth by Sleep
After Captain Hook captures Tinker Bell, he heads to Skull Rock, where Terra is waiting. Terra frees Tinker Bell, but before the angry Hook can act, the Crocodile appears in the water, and Hook runs off. He follows Hook to the Cove, and it circles the platform where Hook and Ventus are fighting. After Ven knocks Hook into the water, Hook is chased back to his ship by the Crocodile. Hook later steals the Lost Boys' treasure chest once again and takes it to the gully, but when he opens the chest to gloat, he discovers that it only contains the children's keepsakes. Just as he begins to curse in frustration, the Crocodile reappears and scares him off.

Kingdom Hearts
Before Sora is about to walk the plank, the Crocodile has it's mouth open to eat Sora, but Sora jumps off of the Crocodile's neck.Later, after Sora and Peter Pan defeat Captain Hook, Hook falls into the water, only to be chased away by the Crocodile.

Origin
The Crocodile first appeared in J.M. Barrie's Peter Pan then came to Disney's Peter Pan (1953).

Supposedly, the Crocodile ate Hook's hand because of Peter Pan, and so Hook had to get a hook for a hand and is frightened whenever the Crocodile appears, and in turn angry when Peter Pan appears.