Want a Whopper for lunch for just a penny? Then all you have to do is head to your nearest...McDonald's. That's right: To celebrate its new app, Burger King is giving customers the chance to score a one-cent Whopper by basically trolling McDonald's. All you have to do is download the BK app, then get within about 600 feet of a Mickey D's franchise. That'll apparently trigger the special one-cent deal on the app, and then you just pick up your burger at the nearest Burger King. The fast-food chain says in a statement that the app will also guide you to the nearest BK if you need directions. The "Whopper Detour" runs through Wednesday, December 12.