Boo Mario is a form Mario takes on in Super Mario Galaxy via touching a Boo Mushroom. It can only be found in the Ghostly Galaxy and Sand Spiral Galaxy. Mario must find it to save Luigi in a ghost mansion. If the player shakes the Wii Remote, Mario will become transparent and walk trough some walls. He can also levitate a little higher. If Mario runs into a light or gets hit by another Boo, he will revert to normal. Mario also races the Spooky Speedster throughout the galaxy.