School of phantoms
(Book)

It's been months since Levi and Kat defeated the Boojum and rescued their town's forgotten children. But now the strangeness has started again: hundreds of creepy snowmen pop up across town and a bizarre blizzard hits the day before spring break. Being trapped in the school overnight by freak weather is bad enough. But an evil is lurking . . . one far worse than ice and wind. Worse than power outages. Even worse than being stuck with teachers and annoying classmates. Something is roaming the darkened school halls. Something . . . hungry. Now it's up to a small group of student survivors--along with some supernatural helpers--to uncover the cold-hearted menace before it takes the entire school.