Shark

A Jaw is an enemy found in Turtle Zone from Super Mario Land 2: 6 Golden Coins. Normally, it swims slowly, but when Mario gets close to it, it would start swimming faster. Since it is an underwater enemy, Mario can't stomp on it, and fireballs do not affect it. The only way to defeat it is with a Star, or, in one case, a Koopa Shell from the surface. It actually wears boxing gloves, but it didn't seem to use them against Mario.