Mega ? Block
Giant ? Blocks are blocks in Super Mario Bros. 3. Found in Giant Land, and in secret areas, they contain 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. When Mario or Luigi hits one of those Giant ? Blocks, 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. In Mega Mushroom Houses, Giant ? Blocks also appear, but these always give out Mega Mushrooms.
Apparently, In Mario & Luigi: Bowser's Inside Story, Broque Monsieur has one in his collection, but it's unobtainable throughout the game.
They appear, albeit rarely, in New Super Mario Bros. Wii. Here, they are pretty much the same as the ones in New Super Mario Bros., except they are yellow and cannot release Blue Shells. Instead, they can also release Stars and 1-Up Mushrooms.
In Super Mario Galaxy 2, they appear in the Supermassive Galaxy. Mario and Luigi are unable to hit these blocks, and they are merely used as platforms throughout the level.
