Screwtop Shroom

Purple Platforms are a type of Mushroom Platform found in the New Super Mario Bros. sub-series.

New Super Mario Bros. Wii
Purple Platforms first appear in New Super Mario Bros. Wii. Some of them have a screw on top of them which needs to be spun to activate the corresponding set of purple platforms and make them move. They slowly move back in the direction they came from when the player is not spinning the corresponding screw. Only four of them appear in the entire game, specifically in World 1-5 just before the checkpoint.

New Super Mario Bros. U / New Super Mario Bros. U Deluxe
Purple Platforms return in New Super Mario Bros. U and its remake, exhibiting the exact same behavior as in New Super Mario Bros. Wii. They only appear in Rising Tides of Lava. They are very common in the course. Purple Platforms are among the objects that do not return in New Super Luigi U.