Finn Family Moomintroll, Paperback/Tove Jansson

Cheerful Moomintroll lives in the magical Moominvalley with his mother, Moominmamma, his father, Moominpappa and all of their friends. One spring he wakes up to find a big hat - a magical Hobgoblin hat, no less, that mysteriously transforms anyone - or anything - that falls into it . . .