Chain: KFC
Introduced: 2010 

Buns have held back the sandwich game for too long. They get in the way of what the people really want: more fried animal. Thus, the brilliance of KFC's creation— two pieces of fried chicken instead of bread—originally announced on April Fool's Day. Jokes, KFC—we see you.

Of course, adding bacon to the equation is pure genius. The sandwich could use more bacon, actually, but at the end of the day the Double Down is more of a conceptual artwork.