Lava Drop

Lava Drops are small, floating, fireball-like enemies found in Super Mario World 2: Yoshi's Island, Yoshi's Island: Super Mario Advance 3, Yoshi's New Island, Yoshi's Woolly World and Poochy & Yoshi's Woolly World, seemingly resembling Lava Bubbles from Mario games. They move either up and down, or left and right. The player cannot destroy them with regular attacks, and as a result, they have to be avoided completely. They appear in various cave levels and in groups. They can be defeated by passing through a Checkpoint Ring, using a Winged Cloud item or with an Anywhere POW.

Super Mario World 2: Yoshi's Island

 * Official Nintendo Player's Guide: Definitely inedible. Like all good dinos, Yoshi knows not to play with Lava Drop.