Maurice gives Darrin a magic lighter with a perpetual calendar. Maurice says that he enchanted the lighter and it will allow Darrin to have powers of witchcraft whenever he wants, which Darrin doesn't accept. Maurice turns Darrin into a donkey because of his ingratitude.
Note: Dick York appears briefly in this episode. He collapsed on the set during filming and was rushed to a hospital, where it was decided he would leave the show.