Fwoosh

Fwoosh is a cloud enemy that first appeared in Super Mario 64. It attacks by blowing strong gusts of wind in order to push characters off high altitudes.

Super Mario 64
In Super Mario 64 and Super Mario 64 DS, Fwoosh will blow Mario and his hat off Tall Tall Mountain. Mario can't defeat it but Wario can walk right past it. The mountain wall near it is a portal to a secret slide. Yoshi also has the ability to eat Fwooshes.

It later appears in the Rainbow Ride mission Somewhere Over the Rainbow where if one of the four heroes is shot in the wrong direction, he will fall into the pit after being blown away by Fwoosh.

Mario & Luigi: Partners in Time
A Fwoosh makes a very small cameo in Mario & Luigi: Partners in Time. The cloud appears to blow away the smoke from Thwomp Volcano after the mountain's eruption is put out.

Mario Party series
Fwoosh has also made many appearances in the Mario Party series. It's proven there that one can stand on a Fwoosh, because in Mario Party, the player can, in Mini-Game Island, warp from world to world by hopping on it. Fwoosh will also bring the player back to start in Mario's Rainbow Castle, again by stepping on him. In Mario Party 3, the player will automatically jump on Fwoosh when jumping at the last block of Awful Tower.

Trivia

 * In its remake, Fwooshes' face bears a small resemblance to Balloon Boo.
 * It is possible that a Fwoosh is a sub-species of a Lakitu's Cloud.
 * A similar enemy called a Foo appears in New Super Mario Bros. Wii. But Foos only blow clouds so Mario cannot see where he's going, not to blow him away.