Hard Block

A Hard Block is one of the many blocks in the Mario universe. They are most commonly used to make stairs that the player can climb. Unlike ? Blocks and Brick Blocks, Hard Blocks cannot contain anything. Hard Blocks can be destroyed with a Bob-omb's explosion, Bowser in Super Mario Bros. 3, and Mega Mario. In Super Mario Maker, Big Koopa Troopa shells can also break Hard Blocks, along with giant Thwomps.

Super Mario Bros. / Super Mario Bros.: The Lost Levels
Hard Blocks made their debut in Super Mario Bros., and reappear in Super Mario Bros.: The Lost Levels with the exact same appearance and purpose. They are notable in both games for being used as stairs at the end of almost every non-castle level leading to the top of the Goal Pole.