When Alexander and his friends find a very large footprint and piles of candy everywhere, they realize the school is being threatened by a Pi�nata-saurus Rex, a sweet-tasting monster who likes to smash things--and they find that the solution may be as near as a broken ant farm.

The latest monsters threatening Stermont Elementary are shadowy shapeshifters that attach themselves to people, eat their shadows, and block out all light--but before he can think of a way to deal with them, Alexander has to deal with a startling revelation from his friend Nikki.

Alexander and his new friend, Rip, are worried that the worms the rain has brought out are really the megaworms that Notebook of Doom describes but they soon discover that the night crawlers are trying to warn them about the monster tunnel fish that are threatening Stermont Elementary.