Super Mario World/Enemies/Spiny

The spinies are little spiked monsters that crawl on the ground. Spinies are almost equal to ordinary Koopa Troopas, except for that they have a very spiky shield. If you flip them over, you can shoot them just like a normal Koopa shell. Lakitu often throws these from his cloud. Although Spinies don't look like delicious treats, Yoshi can swallow them, spikes and all. But Mario will be injured if he tries to stomp them.

Resistance to attacks
Yoshi's fireballs: It does the same as a normal fireball, so Spinies will turn into a coin when they're hit with a fireball.
 * Normal jump: Not very effective, it won't harm Spinies at all, but it only gives you very sore feet
 * Spin jump: Not effective, but at least it won't hurt you, Mario will bounce off.
 * Jump with Yoshi: Not effective (it won't harm them), but you can use this to jump high with Yoshi
 * Fireballs: When a fireball hits a Spiny, the Spiny will turn into a nice golden or silver coin
 * Yoshi's tongue: With Yoshi, you can pick Spinies up and if you're playing with Luigi, you can spit them out

Locations

 * Almost everywhere
 * Specifically: Forest of Illusion 4