This form first appeared in Super Mario Galaxy in the Ghostly Galaxy. If Mario obtains a Boo Mushroom, he will turn into Boo Mario. Boo Mario can float by pressing and turn himself invisible by shaking the Wii Remote, making Boo Mario go through solid walls. If he flies into a light, he turns into regular Mario. The Boos in the area that Boo Mario is in will become infatuated and follow him around. Boo Mario races the Spooky Speedster in one level in order to gain a Power Star. In another, he rescues Luigi.
Super Smash Bros. Ultimate
Boo Mario appears as a spirit in Super Smash Bros. Ultimate. If the player obtains the spirit, the player's jump and move speed will increase, but will be easier to be launched.