Elf on the Shelf is a popular holiday tradition where children receive a special elf figurine who magically comes to life and watches over them. The elf is usually found perched on a shelf or hiding in a different spot each morning, and the children can interact with the elf, asking it questions or sharing their Christmas wishes. At night, the elf returns to Santa to report on the child's behavior and ensure Santa knows who's been naughty or nice. Many stores sell Elf on the Shelf kits during the holiday season, which typically include a plush elf figurine, a book, and a set of holiday accessories.