What Happens When You Order Off-Menu Items at McDonald's

April 3, 2014— -- Fast food fans are in for a treat.

A website dedicated to exposing secret off-menu items at chains spilled the beans about delicacies like Taco Bell’s Superman Burrito and KFC's Poutine.

But an employee at McDonald’s gave one ABCNews.com reporter in New York a weird look when she ordered the McGangBang, a horrible name for what HackTheMenu.com claims is a McChicken Sandwich stuffed between the buns of a McDouble burger.

And at Subway, a worker was confused when we requested the “pizza sub,” purportedly another secret dish.

Some are already well-known off-menu favorites -- like In-N-Out’s “animal style” burgers and fries.

Many of the items listed on HackTheMenu.com, which calls itself “the ultimate collection of secret menus," are actually featured items that were once on the chains’ menus, like Subway’s “old cut” subs and Burger King’s Rodeo Burger, a beef patty covered in cheese, onion rings and barbecue sauce.

At Starbucks, employees were well aware of a secret menu and said customers order from it frequently. They just needed a reminder of the ingredients -- handily listed on HackTheMenu.com -- to whip up a delicious Thin Mint Frappuccino.