How does Santa really know who is naughty or nice? The answer is finally revealed in...The Elf on the Shelf A Christmas Tradition.TMThe Elf on the Shelf A Christmas TraditionTM is an activity the entire... goodreads.com
Definition #2 for "elf on the shelf"
Elf on the Shelf is a Christmas-themed elf doll and the protagonist character of the 2005 children?s book with the same name. Since its emergence to mainstream popularity, the decorative figurine has inspired parody photographs in which the Elf is staged in a wide range of erotic, creepy or otherwise disturbing settings, in similar vein to Hentai Woody and other figurine-based photo fads.