The Elf on the Shelf is a popular Christmas tradition that began as a children's book written by Carol Aebersold and her daughter Chanda Bell. The book, first published in 2005, tells the story of a magical scout elf sent by Santa Claus to watch over children during the Christmas season and report back to Santa on their behavior.

The accompanying elf figurine is typically a small, poseable elf with a mischievous and playful expression. Families that adopt the Elf on the Shelf tradition place the elf in different locations around the house each night while children are asleep. The idea is that the elf returns to the North Pole each night to give Santa an update on the children's behavior and then returns to a new spot in the house before the kids wake up.

The elf is often depicted engaging in playful or mischievous activities, and part of the fun for children is waking up each morning to discover where the elf is hiding or what antics it has been up to. This tradition has become a beloved and widespread part of many families' holiday celebrations, encouraging good behavior in children as they believe the elf is watching and reporting back to Santa.