Denny’s wants in on the Burger King-McDonald’s mashup burger by Michal Addady @FortuneMagazine August 31, 2015, 1:40 PM EDT E-mail Tweet Facebook Linkedin Share icons After McDonald’s rejected Burger King’s proposal for a mashup burger, Denny’s recognized a potential business opportunity. Burger King very publicly suggested that it “end the beef” with McDonald’s by collaborating on a burger in honor of Peace Day on September 21. They took out full-page ads and even set up a website explaining that all “McWhopper” proceeds would benefit a non-profit organization called Peace One Day. McDonald’s CEO Steve Easterbrook responded the offer on Facebook, rejecting the idea and ending with “A simple phone call will do next time.” After seeing this, Denny’s took to Twitter with a proposal of its own. It wants to combine its own Bacon Slamburger with Burger King’s Whopper to make a “Slopper,” or something else that sounds a bit more appetizing: hey @burgerking …or the Whoppaslam©? The Slopper©? The Slamopper©? wouldn't that be whopperslamalicious?! https://t.co/t1FACtBhgv — Denny's (@DennysDiner) August 29, 2015 Denny’s isn’t the only one trying to get in on Burger King’s Peace Day deal. Krystal, an Atlanta-based fast food restaurant that specializes in sliders, also extended an offer to the royal fast food giant via Facebook: We’d be honored to join y’all (Burger King and Peace One Day) in continuing your day of peace in Atlanta. We propose working together to create the first tiny square Whopper. (We’re partial to the Kropper, the Whystal, or the Tiny King.) Burger King has not responded to either offer.