An "elf on the shelf" is a Christmas tradition that originated in the United States. The tradition involves placing a small elf doll, which can be purchased from various retailers or made at home, in a hidden location within the home during the Christmas season. The elf's role is to act as Santa's scout, reporting back to the big man in red on the children's behavior. Each day, the elf is relocated to a new spot, and children can try to find it and interact with it.