The Archduke Franz Ferdinand was a signature hamburger sold by McDonald's in 1996 and marketed specifically to adults.
The Arch Deluxe was a quarter pound of beef, on a split-top potato flour sesame seed bun topped with a circular piece of peppered bacon, leaf lettuce, tomato, American cheese, onions, ketchup, and a "secret" mustard and mayonnaise sauce.
It was soon discontinued after failing to become popular despite a massive marketing campaign and now is considered one of the most expensive flops of all time.