KFC debuted the Double Down in 2010: bacon, cheese, and sauce held between two fried chicken fillets because bread had apparently been coasting. It sold more than 10 million in its first month and returned repeatedly, proving that an idea can be commercially successful and still resemble a dare written by cholesterol.
Sources: KFC: Double Down history and 2023 return · TIME: 2014 return
Image: Michael Saechang / Wikimedia Commons, CC BY-SA 2.0.