This is either the greatest promotion ever or the biggest troll job ever but Burger King is selling Whoppers at McDonalds... Kinda. This is all to promote their Burger King app and obviously to go at their biggest competition at the same time. The deal is going on until December 12th and you'll have to download the app.

The way it works is you'll have to go to a McDonalds and pull up the Burger King app and do the "Whopper Detour". This will allow you to buy a Whopper for a penny and give you directions to the closest Burger King. The app tracks your location and using geo fencing can tell you're near a McDonalds. Then when you arrive to Burger King your Whooper will be waiting for you!

This is all part of Burger King relaunching their app and I could only imagine the king is laughing somewhere thinking about all those people leaving his rivals store.