Justin Timberlake and Jessica Biel posted Instagram photos and videos of the cheeky Elf on the Shelf displays set up for their sons Phineas and Silas in honor of Christmas.

Elf on the Shelf is a wildly popular Christmas phenomenon that not even the leaders of Christmas (AKA Santa and Mariah Carey) could have seen coming. Opinions about Elfie are pretty polarizing ...

The pitch captivated sharks Lori Greiner and Robert Herjavec, who grabbed 15% ownership of the business for $150,000.