Burger King launched a campaign last week asking McDonald's to team up and make a "McWhopper" for International Peace Day later this month. But McDonald's politely declined the offer. A few other companies said they'd be open to collaborating. Denny's, Krystal, Wayback Burgers, and Giraffas were just a few who came forward.

Burger King posted an open letter on Facebook saying that they'd love to collaborate with all of those chains, with everyone contributing one ingredient to the burger. It would be for sale at a pop-up restaurant in Atlanta on Peace Day, which is on September 21st.