Boos (originally known as Boo Diddlys[1] and later Boo Buddies[2][3]) are common ghost enemies in the Mario franchise that first appear in Super Mario Bros. 3. They are a type of white, spherical ghost with menacing and normally open mouths. They are known for their large tongues and small arms of some sort. However, the most distinctive characteristic of the Boos is their shy personality, where they cover their faces when someone looks them directly at the face. They will uncover their faces once the subject turns around. Goombarios tattle for the Boo Igor in Paper Mario states: He probably was a merchant before he became a Boo, implying that current Boos may have once been living beings. It is revealed in Super Mario Galaxy that they speak in Booish.