Foo

Foos are white cloud-like enemies that appear in New Super Mario Bros. Wii, New Super Mario Bros. U, and New Super Luigi U. 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. Foos can be attacked by tapping it in Boost Mode, but they'll reappear in a few seconds.

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

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