Alligator

The Alligator is a boss that appears near the end of the sewer section in Resident Evil 2.

The Alligator can be killed by simply shooting it, this causes it to smash a hole in the wall and escape. Killing it in this way cause a small amount of ammo to appear a little later on.

The other method (Often know as the 'secret' method) involves releasing an emergency gas can, which the Alligator picks up in its mouth. When the canister is shot, it explodes along with the Alligators head. Killing it in this way means it can be killed with 1 hand gun round.