A Used Block is what a Question Block looks like after it has been used. They appear in Mario games. When you've used a Question Block, it will turn into a Used Block. Used Blocks are brown with four holes in their corners. You can't get anything from a Used Block, so you must leave it alone. It is impossible to find a block already used when you haven't touched it yet. Because Question Blocks appear in every level, Used Blocks appear in every level as well.