In-N-Out is an iconic regional fast food chain, but many may not realize there is a "Not So Secret Menu," which lets customers slightly modify their orders regarding quantity and specific ingredients. There are even some extra secret items available at In-N-Out that the company does not openly acknowledge.

One of these is the Flying Dutchman, which includes two patties with slices of American cheese between them and no bun (per In-N-Out). You can add grilled onions, peppers, or pickles, but you'll want to eat this messy delight with a fork and knife.

Because the name "The Flying Dutchman" references a legendary ship, perhaps the brown meat is supposed to resemble a wooden ship, and the yellow cheese is its sails. The former Chief Executive Officer, Guy Snyder, created the Flying Dutchman, but as the site does not give his rationale for the moniker, the name might just be a mysterious part of its appeal.