- Not to be confused with Big Boo.
Sleepy Boos are a variant of Big Boos featured in Super Mario Sunshine. Their sole appearance is in Episode 3: Mysterious Hotel Delfino of Sirena Beach, as an obstacle blocking Mario's path.
Sleepy Boos are always found asleep, blocking passages, especially in the narrow passages within the attack. Mario cannot awaken a Sleepy Boo, but if he touches one, he takes one unit of damage. The only way to defeat a Sleepy Boo is by having a Yoshi eat it.