Ghost Block

A Ghost Block is a very rare, possessed ? Block that appears in New Super Mario Bros. Wii. Only 4 of them appear in the secret area in World 7 Ghost House. They guard a Star Coin. They resemble a normal ? Block, but as Mario approaches, they turn purple as they float over the character and throw themselves at him (a very similar mechanism is used by a Ghost Vase), breaking apart and releasing a Coin if they hit the floor or a platform.