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Mushroom Platforms (originally known as Super Mushrooms) are semi-solid platforms that are shaped like a mushroom. These platforms were introduced in Super Mario Bros., where they were initially solid platforms. Mushroom Platforms have since appeared in most Mario games.
Super Mario series
Super Mario Bros. introduces Mushroom Platforms in World 4-2's Warp Zone, and are featured again in World 4-3. In Super Mario Bros: The Lost Levels, Mushroom Platforms are replaced with cloud platforms at the end of World 8-2 (since the Goal Pole can only be accessed via Beanstalk), in World 8-3 (which takes place in the sky), and in World A-3; although Mushroom Platforms in the style of those in Super Mario Bros.: The Lost Levels appear in All Night Nippon Super Mario Bros., where their stalks are broken up into segments.
A similarly-themed object known as a Mushroom Trampoline that appears in New Super Mario Bros., Super Mario 3D Land, New Super Mario Bros. 2 and Super Mario 3D World act similar to a Springboard or Note Block.
Mushroom Platforms appear as placeable objects in Super Mario Maker and Super Mario Maker for Nintendo 3DS. Their height and length can be adjusted in the level editor. When Mushroom Platforms are placed underwater, their appearance changes to resemble coral. When they are placed in airships in all styles except for New Super Mario Bros. U, their stalks change, and in the Super Mario Bros. style, the cap becomes metallic.
Super Mario World 2: Yoshi's IslandYoshi's Island series, Mushroom Platforms first appear in Super Mario World 2: Yoshi's Island. In this game, Mushroom Platforms appear in cave levels, with many having much thinner stalks and caps, which curve around more than the blocky squarish ones from most Mario games. They come in multiple colors, such as red, blue, beige, and purple, and have a whitish center area instead of spots. Thicker ones with triangular caps also exist, and do have spots. Smaller examples of these can come in other colors, such as dark mahogany and dark pine green, while even smaller than that are limited to blue, red, beige, and purple, like the largest ones. Most of both types appear to have a slice out of the cap, but the smaller two versions of the latter type lack these.
Mario Kart series
In the Mario Kart series, Mushroom Platforms first appear as a cameo in the background of Mario Circuit in Mario Kart: Double Dash!!. Mario Kart Wii features a track themed after them, Mushroom Gorge. Green Mushroom Platforms are standard platforms, while the player can bounce off the red Mushroom Platforms, and can glide off of blue Mushroom Platforms, the last of which only appears in the Mario Kart 7 Retro Course.
Super Smash Bros. series
Mushroom Platforms appear in the backgrounds of the Mushroom Kingdom stages of Super Smash Bros. (where they are green rather than orange) and Super Smash Bros. Melee. They also appear in the Golden Plains and Rainbow Road stages in Super Smash Bros. for Nintendo 3DS. The ones in the former stage are pass-through platforms, while the one in the latter is not, as it is one of the stage's main fighting arenas.