Apparently, the "secret menu" at McDonald's is a real thing and not just an urban myth.

A manager at a McDonald's in Glasgow, Scotland, acknowledged the existence of secret menu options during an "Ask Me Anything" thread on Reddit titled "IamA McDonald's manager AMA!" 

"Have you ever wondered exactly how your fast food is made? Or what it's like to work for one of the biggest food giants in the world? I've been working for McDonald's for 3 years throughout college/Uni and now that I've graduated.. still working for McDonald's as a manager," wrote the anonymous restaurant manager, who goes by the user name "orchidhibiscus," in a blurb over the weekend.

The fast food worker revealed that customers can order from a list of unique and even outlandish off-the-menu sandwiches at the restaurant chain. For instance, "The Land, Air and Sea burger" is a nickname for a Big Mac, McChicken and Filet-O-Fish combined into one sandwich. Patrons also have the option of ordering the "McGangBang," which consist of a McChicken sandwiched inside of a double cheeseburger.

"You can order from the 'Secret Menu'. Just like with any of our sandwiches, you can add, remove or change ingredients by special request. These are called 'grill orders' (i.e. Big Mac no pickle)," said the McDonald's staffer.

"The items on the 'secret menu' weren't invented by anyone officially at McDonald's, it's just a random persons guide to burgers you could potentially 'hack' at McDonald's," he explained.

Even if a worker at the popular fast-food chain is unfamiliar with the name of a sandwich on the "secret menu," customers can still describe the type of sandwich that they want to order and pay for all the extra ingredients, he added.

The McDonald's manager also warned patrons not to order the grilled chicken, saying, "It's horrible frozen chicken that we defrost and steam and it's a bit gelatinous."

In addition to "The Land, Sea, and Air Burger" and "McGangBang," Hack the Menu has a complete list of McDonald's offerings collected from secret menus at different restaurants. Included on the list are the "Chicken McGriddle," "Big McChicken," "Monster Mac" and "McCrepe."