Foo

Foos are white cloud-like enemies that first appeared in New Super Mario Bros. Wii. They produce fog that can obscure the player's view. Foos can be defeated with any kind of attack. Their name comes from the Japanese onomatopoeia for blowing sounds.

New Super Mario Bros. Wii
New Super Mario Bros. Wii marks Foos' debut appearance. They act much like a Fwoosh from Super Mario 64 and its remake, though Foo's wind only produces fog, and does not blow Mario away. They appear only in World 7-5.

The fog vanishes after a few seconds and can be blown away by Spin Jumping or propelling Propeller Mario.

New Super Mario Bros. U
In New Super Mario Bros. U, Foos appear only in Snaking above Mist Valley and behave the same as they did previously.

New Super Luigi U
Foos also appear in New Super Luigi U. Here, they are only found in Three-Headed Snake Block.

Super Mario 3D World
Although no original Foos appear in Super Mario 3D World, a derivative called Ty-foos are introduced. Ty-foos function more as obstacles rather than enemies. They blow a strong gust of wind that pushes the player and projectiles, such as Fire Flower fireballs, in the opposite direction, usually into another obstacle such as spikes or a pit. Heavy enemies like Bullies are unaffected by the Ty-foos' gust. Most Ty-foos are stationary, but some can move left and right while blowing. They can be stunned with fireballs and boomerangs, but Ty-foos can be defeated only by star invincibility, an Invincibility leaf, or a Mega Mushroom.

Mario Party 10
Foos play a role in the Mario Party 10 minigame Foo Me Once, where they blow fog over platforms the players need to remember.