When Nick Cannon sent Kevin Hart a live llama to his house as a birthday present, it could have been "one and done" and well played by Nick, but it wasn't. Kevin Hart retaliated by paying for several expensive billboards in several major cities displaying Nick Cannon's private cellphone number. This story made headlines across the country. It was so funny and unexpected that now Kevin and Nick's celebrity friends want in. Every episode of "Celebrity Prank Wars" will feature two new celebrities planning, plotting and perpetrating some of the biggest, wildest and most viral pranks on each other in hopes of being judged the winner of the prank war.