Rock Mushrooms are power-up items in Super Mario Galaxy 2. They transform Mario into Rock Mario, and when collected, Mario's hat and overalls turn into stone, and it gives Mario the ability to encase himself in a boulder upon shaking the Wii Remote once.
In this form, Mario can roll around, jump, damage enemies, and destroy red crystals with items in them. However, when he comes into contact with a crystal or a certain type of enemy, he will revert to his rock form. However, players can always return to his boulder form by re-shaking the Wii Remote. Mario will revert to his normal form if he takes damage or touches a Launch Star.
The Rock Mushroom is of paramount importance in the Boulder Bowl Galaxy.
|Power-ups in the Super Mario Bros. series|
This power has a resemblance to the same move that bowser used in the first game (possibly inspired by that to make this)