An Empty Block (sometimes referred to simply as a Block or a Steel Block) is a type of block in the Mario franchise that usually appears when Mario, Luigi, and their friends hit a ? Block, an item-holding Brick Block, or a Coin Block, though they sometimes are naturally already in an "empty" state. Empty Blocks are usually brown round-edged cubes with small holes in their sides' corners. In Super Mario World, Empty Blocks have small, closed, angry eyes, but no holes; if the player hits a blue P-Switch, all Empty Blocks turn into coins and vice versa for a short time. Empty Blocks can only be broken by Mega Mario or stronger enemies, such as Broozers, King Bills, and Giant Bowser.