Esther Allen Peterson

Frederick is prone to exaggeration and, well, lying. When he's mad at his mother or his teacher or the mailman, he tells them all about his wolf, his bear, his lion in the closet is going to come out one day and harm them. "Sure, Frederick".

Until the day he finds an actual baby alligator and brings it in to show-and-tell, and all of a sudden his doubters aren't sure if he really has all those wild animal pets or not. (He lets the alligator go.)