An iconic ghost enemy from the Mario Series that first appeared in Super Mario Bros. 3, where they were originally named "Boo Diddlys". They have a shy personality, as they will cover their face whenever someone looks at them, but will uncover and chase the player when not being looked at. Commonly found in Ghost Houses.
Boos also appear in the Mario Kart franchise as an item used to steal other items from opponents and will make the user temporary invisible and invincible. They are also playable characters in certain Mario Party, Mario Golf and Mario Tennis games.
Boos are depicted as white spherical ghosts with stubby arms, black beady eyes, sharp teeth and large tongues.
