McWhopper
Burger King has proposed a McWhopper to promote Peace Day. Burger King

Stop the burger wars! Burger King has called for a temporary ceasefire with rival McDonald's, proposing a cross-brand promotion that would see the chains' iconic Whopper and Big Mac burgers combine for a good cause. BK announced it wants to create a McWhopper for Peace Day, Sept. 21.

Burger King dropped a McWhopper video on the Internet, and fans have been eating up the proposal. Burger King's pitch included an open letter to McDonald's to "end the beef, with beef." "Peace One Day is a nonprofit organization campaigning to make Peace Day September 21 an annual day of global unity. They have a powerful rallying call -- 'Who will you make peace with?' -- which has inspired us to lead by example and extend an olive branch of our own," Burger King's letter explained. The McWhopper would combine the best parts of the Whopper and Big Mac and would be developed together by the fast-food giants. The burger would be served in a pop-up restaurant in Atlanta, halfway between the corporate headquarters of McDonald's and Burger King, BK suggested.

But wait: Which patties would be used? Will the secret sauce be on the burger? What about the bun? Whatever the concerns, McDonald's shot the idea down. "We love the intention but think our two brands could do something bigger to make a difference. McDonald's wrote in a Facebook post. "We commit to raise awareness worldwide. Perhaps you’ll join us in a meaningful global effort? And every day, let's acknowledge that between us there is simply a friendly business competition and certainly not the unequaled circumstances of the real pain and suffering of war."

To top it off, McDonald's ended the post with a saucy "a simple phone call will do next time."

The failed McWhopper in the name of peace is still a victory for Burger King, in terms of brand image. BK looks like it wants to have fun, while McDonald's comes across as stiff.