Big Boos first appeared in Super Mario World. In the game, Big Boos inhabited the various Ghost Houses located around Dinosaur Land. Curiously, although they are over ten times bigger than a normal Boo, Big Boos still have the same mannerisms of their smaller counterparts. Of course, this means that when looked at, a Big Boo will fade and hide behind its arms. However, if someone's back is turned, a Big Boo will attack him or her from behind.