The "hangover" burger features a burger patty, Applewood-smoked bacon, American cheese, haystack onions, a fried egg, and Smash Sauce.
The burger is one of a series of unique local burgers that Smashburger offers in each market where they are located. For example, they're currently offering the SoCal here in Southern California; it's a burger with fresh avocado, cilantro, pepper jack, lettuce, tomato, onion, sour cream, and chipotle mayo on a telera roll served with a wedge of lime.
Each local burger is usually only available in their respective markets, but the burger chain recently featured a few of them as limited-time menu items nationwide to keep it interesting.