Mega ? Block

'''Giant ? Blocks' are blocks in Super Mario Bros. 3''. Found in Giant Land, and in secret areas, they contained multiple 1-Up Mushrooms or various Suits, such as the Tanooki, Frog, and Hammer Suits. In Wario Land, there are giant ! Blocks that would activate something on the map screen, usually to make new levels.

They are found in Toad Houses in New Super Mario Bros.. They roll through Super Mushrooms, Fire Flowers, Mini Mushrooms and Blue Shells quickly. In Mega Mushroom Houses, Giant ? Blocks also appear however they always give out Mega Mushrooms. When Mario or Luigi hits the Giant ? Block, the item that it is stopped on will be put in the player's reserve, replacing any item already there, provided that the item in reserve is weaker than the new item.

Apparently, In Mario & Luigi: Bowser's Inside Story, Broque Monsieur has one in his collection, but it's unobtainable throughout the game.

They appeared, albeit rarely, as coin-or-1-UP-only blocks in New Super Mario Bros. Wii.