" star Kellan Lutz
took over "Punk'd
" (Thu., 10 p.m. ET on MTV) for the week, and immediately targeted some of his Hollywood friends. He enlisted three-time "Dancing With The Stars
" champ Derek Hough
to help prank his sister Julianne
. The set-up was pretty simple, with Derek getting out of the car to move an obstruction, and then pretending to fall into a quagmire and get stuck.Julianne certainly fell for it, though she didn't get ...