Super Mario World/Enemies/Magikoopa

Magikoopa is a koopa that has mastered the art of wizardry. He can cast magic spells that look like multicolored geometrical shapes coming out of its wand. If the spell touches Mario, it will harm him. If the spell touches a yellow block, it will turn into something else, like a coin or a koopa. Magikoopa can also vanish and appear somewhere else.

A jump on top of it will defeat it, but it's possible it will appear again.