An object in the Mario series, appearing as a block with a quarter note on it.
Jumping on it causes Mario to bounce up, and also increases his jump height when he jumps off it.
Super Mario Maker introduces the Music Block, a variant with an eighth note on it instead of a quarter note. It plays a short musical note when hit or landed on.
Super Mario Bros. Wonder introduces the Marimba Block, a variant with beamed eighth notes on it. Unlike Note Blocks, they do not cause Mario and the others to bounce up, instead only increasing jump height.