Goosebumps: The Girl Who Cried Monster(1995)

She's got the monster of all problems!

Lucy loves telling monster stories, but her family and friends are tired of her wild tales. So, when Lucy sees a real monster—Mr. Mortman, the local librarian—no one will believe her. If she can just get proof that he is a monster, maybe then they'll listen. But is it too late? Mom and dad have invited Mr. Mortman to dinner! This is sure to be one meal that'll be hard to swallow.