Boo Mario is one of Mario's Power-Ups that first debuted in Super Mario Galaxy. Upon touching a Boo Mushroom, Mario will transform into a Boo (while retaining his original facial features and cap). As a Boo, he will be able to perform any action that the ghostly enemy normally could, namely turn invisible to pass through grates (in a manner not dissimilar to the Vanish Cap from Super Mario 64) and levitate. Interestingly, Boo Mario will attract other Boos, and he can use them to perform various deeds in order to progress in levels.
Unlike most of Mario's other power-ups, which are lost when Mario is damaged by an enemy, Mario can revert from his Boo Mario form through a variety of different methods; this is due to the fact that Mario can not actually be harmed by other enemies while in this form. Mario will revert back to normal should he enter a lighted area, touch water, or touch a Launch Star.
Boo Mario appears as a trophy in Jake's Super Smash Bros..
| ||No, this isn't just another normal Boo; believe it or not, this is Mario! The Boo Mushroom allows Mario (or Luigi) to transform into a Boo. Mario gains all the same things a Boo can do, be it fly through walls, turn invisible, and understand the Boo language. Maybe it's the stylish moustache or the red cap, but the Boos are all drawn towards Mario, as if he's a celebrity. Unfortunately, the Boo Mushroom seems to only be found in outer space, as Mario's only been able to become Boo Mario in Super Mario Galaxy and its sequel.... well, and Puzzle & Dragons: Super Mario Bros. Edition, but nearly every power-up is in that game.|
- Upon transforming into Boo Mario, Mario becomes fluent in the Boo language of Booish.