Boo Mario is the third form that Mario has access to and is found in the Ghostly Galaxy. Boo Mario is obtained once a Boo Mushroom is found. Boo Mario can float and go through some walls (bars,crystal). Boo Mario will transform back to normal Mario once he is exposed to light (either outside light or light from a lamp), is harmed by an enemy or is in a Launch Star or Sling Star. The Boo Mushroom returns in Super Mario Galaxy 2, and makes it's first, and only appearance in this game, in the Boo Moon Galaxy.