You many think that the regular old Big Mac is the pinnacle of hamburger decadence. You are wrong. The "Monster Mac" is precisely what it sounds like: a hulking version of the flagship McDonald’s sandwich, with eight patties, globs of cheese, special sauce, lettuces, pickles, and onions (that extra piece of bread on the menu-sanctioned Big Mac will be included upon request).
Burgers of the ‘Monster Mac’ variety aren’t limited to McDonald’s; several major burger chains have secret versions of their own. Burger King has the “Suicide Burger, with four beef patties, four slices of cheese, bacon, and special sauce. Wendy’s offers the “Grand Slam,” also with four patties. But the top dog in the grotesquely large secret burger game is In-N-Out. The California-based chain will grant burger requests of just about any size. Seriously: According to In-N-Out legend, a group of friends in Las Vegas successfully ordered a burger with 100 patties in 2004.
Restaurant chains deal with the secrecy issue in different ways. In-N-Out and Panera actively promote their secret menus on the web. McDonald’s, Burger King, and Starbucks, meanwhile, have publicly denied the existence of any published secret menus while softly encouraging customers to go ahead and order away. “While we can confirm that our menu items are highly customizable, the “secret menu” will remain as such and brand prefers to continue rewarding its guests who exercise their right to HAVE IT YOUR WAY®,” a Burger King representative wrote ABC News last year.
"Customers have come up with their own McDonald's items," spokeswoman Danya Proud told USA Today. But whether or not restaurants will sell them that way is "decided on a restaurant-by-restaurant basis."