Crocodiles are enemies which you will face throughout the game.
Unlike most other enemies, the crocodiles are only capable of biting, and possess no long range attack or weapon. Their bite attack, however, is extremely powerful, and they are the quickest enemy in the game. They also have one of the highest HP/energy points for a standard enemy, making them somewhat troublesome when in large groups (which, most of the time, they are).
If you are playing through the game in the order set out for you, you will first encounter them in Lower East Quack.