Super Mario World/Enemies/Jumpin' Piranha Plant

Jumpin' Piranha Plants hide in pipes and jump up to snap at Mario or Luigi, before retreating back into the pipes. However, they will not jump if Mario or Luigi is right next to the pipe.

You cannot defeat them by regular jumps - as a matter of fact, they will hurt you that way. Spin jumps and Yoshi jumps will snap off Jumpin' Piranha Plants. These plants, however, can be defeated easily by fireballs, cape spins, and collisions with Koopa shells and grab blocks. Yoshi can also eat them. These plants can be defeated while inside their pipes.

Beware that in later levels, certain Jumpin' Piranha Plants can also throw fireballs.