Foos are enemies that appear in the console New Super Mario Bros. games. They make fog so you won't be able to see where you're going in a certain stage. They act sort of like a Fwoosh from Super Mario 64 and Super Mario 64 DS. They are found in three levels in the entire series: 7-5 (Wii), Snaking above Mist Valley (U), and Three-Headed Snake Block (Luigi U). Bigger stronger versions called Ty-Foos appear in Super Mario 3D World and Super Mario Odyssey.