The moon in Swampland - M. P. Robertson

Whenever the Moon's back is turned, the wicked bogles terrorize the townsfolk, coming out of their slimy holes to lure unsuspecting travelers to their doom. One night the Moon takes human form to rescue Thomas, a boy from the village who is lost in the marshy mist. In saving him, however, the Moon is captured by the bogles and imprisoned in a watery hole. With no natural light at night to keep the bogles at bay, the townsfolk live in mortal fear until Thomas decides to end the evil sprites' reign of terror. Gorgeously illustrated atmospheric images and a powerful folk narrative make this an ideal first horror picture book.