what's an elf on a shelf

An elf on a shelf is a little elf toy that can be purchased at stores around the world. It is designed to be placed on a shelf and has a mechanism inside that makes its eyes move and makes it wave its arms around. The purpose of the toy is to help parents keep an eye on their children's behavior during the holidays, as the elf supposedly reports back to Santa Claus if a child has been naughty or nice. Some people also use the toy as a fun holiday decoration.