For decades JK has been the king of stunts and the ultimate prankster ... and this time is no different, dust off your coolest Ray-Bans and see if you can nail the sneaky switches right where it counts!

The "Jackass" and "Bad Grandpa" star was recently hanging backstage playing catch and was clearly ready to throw you this week's 'Frigin' Diff?!' Can you sort through Knoxville's pitching pics and find the changes in the two snapshots?