The Boo Mushroom is a type of Mushroom that appears in Super Mario Galaxy. It is white with the face of a Boo. It is the rarest item in the game, appearing in Ghostly Galaxy, Sand Spiral Galaxy, and Boo's Boneyard Galaxy. They are likely to appear out of a Question Block. When Mario touches the Boo Mushroom, he becomes Boo Mario. There are the goods and the bads with this Mushroom. Mario can go through walls and fly like a Boo can. He can become intangable if the player shakes the Wii Remote. This allows Mario to go through the object. Boos are attracted to Boo Mario, returning him to normal if they touch him. The only other way to become Mario is to go into a light.