It’s the week before Christmas and sitting on the shelf is Santa’s little helper — a mischievous elf! “Elf On The Shelf” is a holiday staple helping Santa Claus keep track of those on the naughty and nice lists. Now, the beloved holiday character is turning 20 years old. ABC News’ Will Ganss sat down with the co-creators, twin sisters who founded the business with their mom. #ElfOnTheShelf #Christmas #Holiday #SantaClaus #ABCNews