Super Mario World/Enemies/Mechakoopa

Mechakoopas are wind-up toy robots shaped like a Koopa. They're actually quite useful, for example in the final battle against Bowser. Bowser will randomly throw two down at a time. They must be stomped, then thrown back at Bowser. Note that if you have jumped on them, they come back to life in a few seconds, so you need to throw them away as fast as possible.

Resistance to attacks

 * Normal Jump: A single jump will make them shrink, to defeat them, just jump another time on them
 * Spin Jump: Very effective, a spin jump will defeat them instantly
 * Jump with Yoshi: N/A, you can't jump with Yoshi on them, since they're only in Bowsers Castle.
 * Fireballs: Ineffective, it won't harm them
 * Yoshi's tongue: N/A, since Yoshi can't enter the castle
 * Yoshi's fireballs: N/A, since Yoshi can't enter the castle
 * Slow cape landing: It will do the same as when you smash them with your cape by pressing Y in the SNES version, or just by pressing B in the GBA version
 * Sliding down a hill: It will defeat the Mechakoopas

Locations
Bowser's Castle