Elf on the Shelf is a beloved holiday tradition where a small elf doll is placed in various spots around the home. Each night, the elf "flies" to the North Pole to report to Santa on children's behavior. The elf returns each morning to a new location, creating excitement and fun for kids. Introduced in 2005 by Carol Aebersold, it has since become a popular Christmas activity, expanding into books, toys, and TV specials.