Jack Vale is one of YouTubes most popular prankster. Some of his most popular videos include "The Fugitive Prank", "Farting on People", "Wife on a Leash", and others. His latest prank on unsuspecting pedestrians involves asking random people to take his picture with his iPhone. What they don't know is the iPhone is loaded with an app that will spawn a zombie ghost that walks across the screen as the photo is about to be taken. Watch the video below.