Shark

Jō (ジョー, a pun on the name "Joe" and ジョーズ Jōzu, meaning Jaws) is a shark enemy found in Turtle Zone in Super Mario Land 2: 6 Golden Coins. Normally he swims slowly, but when Mario gets close to him, he starts swimming faster, charging at him. Since he is an underwater enemy, Mario can not stomp on him, and unlike many other enemies Fireballs do not affect him. The only way to defeat him is with a Star, or, in rare cases, a Koopa Shell from the surface. He wears boxing gloves, but he doesn't seem to use them against Mario.

In volume 9 of the Super Mario-Kun, Mario, Luigi, and Yoshi encounter a Jō during their boat trip. The Jō attacks them, but Mario throws Yoshi to the Jō to defeat it, although Yoshi gets injured.