Mostly ghostly - Who let the ghosts out?

the long version

Max's life wasn't going so well even before two ghosts moved into his closet. But when Nicky and Tara show up, claiming that they used to live in his room, everything changes for Max! Soon they're following him to school, using their invisibility to embarrass him in front of the girl of his dreams. And to make matters worse, there's some other totally evil spirit named Phears following him around turning animals inside out!From the Hardcover edition.