Boo Boo is the cute little mansion's ghost. His job is to haunt. Unfortunately, it's a little difficult for him to do that when everyone thinks he's cute, since he hates being thought of as cute. When he first arrived at the mansion, Boo Boo wasn't an official ghost in that he couldn't phase through walls and only cats, psychics and crazy street preachers could see him. According to the leaders of the Ghost Family (two large, mobster-type ghosts who go by the names of Mr. White and Mr. White), Boo Boo couldn't become a full ghost until he had scared at least one person and Ruby's mansion was the house they'd selected for him. But since Boo Boo couldn't go through walls and Doom Kitty was the only one in the house who could see him, his job was next to impossible. However, when Doom Kitty splashed milk on him to reveal his presence, Boo Boo got a slight scare out of Misery when he almost splashed milk onto a tablecloth owned by Misery's "great-great-really-great"-grandmother. Apparently, it was enough of a scare for Boo Boo to become a full fledged ghost, since he can now phase through walls and everyone can now see him. After that though, his only real motivation for staying in the mansion has been to torture Scaredy Bat, as he hasn't been able to scare anyone else since. However, Boo Boo enjoys pranking more than he enjoys scaring much to two Mr. White ghosts' anger. Despite this he and Scaredy Bat appear to be close friends.