Cloud Drop

Cloud Drops, also referred to as Blusties or erroneously Gusties, are cloud monsters that fly in a short line vertically or horizontally in Super Mario World 2: Yoshi's Island, Yoshi's Island: Super Mario Advance 3, Yoshi Touch & Go, Yoshi's Island DS, and Yoshi's New Island. They appear in packs and in areas where Yoshi can turn into a Helicopter. The move quickly, but they can be defeated with a hit on the head.

In Yoshi's Woolly World, enemies resembling Cloud Drops, known as Wiks, appear.

Super Mario World 2: Yoshi's Island

 *  Official Nintendo Player's Guide: Watch out for these wherever the billowy white stuff is found on Yoshi's Island.