The Elf on the Shelf is a popular Christmas tradition that involves a small elf doll, typically a Scout Elf, who is sent by Santa to keep an eye on children's behavior and report back to him. The Scout Elf arrives on the day after Thanksgiving, which is known as "Elf on the Shelf Day," and stays until Christmas Eve when he or she returns to the North Pole with Santa Claus. The Scout Elf's mission is to encourage children to be good and remind them that Santa is watching them.