From Minecraft Wiki
Mushroom may refer to:
Mushrooms - a naturally-occurring non-solid block found in dark places. It has red and brown variants, and is an crafting material for mushroom stew.
Huge mushroom - a generated structure, a variant of small red and brown mushrooms.
Mushroom (block) - a solid block that comprises huge mushrooms.
Mushroom Stew - a food item crafted with mushrooms and a bowl.
Mushroom Island - a rare biome made up of mycelium and mushrooms.
Mooshroom - a cow variant 'infected' with red mushrooms that only spawns on mushroom islands.