This is most likely the signature burger of the Bison Burger franchise. Unlike the other burgers on its menu, it has to be ordered several days in advance, due to the amount of meat and preparation time needed. It is apparently 4 large burgers stacked on top of one another. Mr. Big Horn made it as a thank you to Fatman for helping him out. Incredibly, even Fatman wasn't able to finish it completely in one sitting.
From the image the ingredients are multiple burger patties, bacon, cheese and other assorted toppings. It is held together with a large skewer and has a toothpick with an American flag on the top.