In-N-Out Burger arguably invented the concept of the secret menu, and 'animal style' fries might just be the most famous ‘secret’ item of them all. For those not yet in the know, asking for your fries ‘animal style’ will get them topped with cheese, In-N-Out secret sauce, and grilled onions. Messy, but so good. Take note: you can also get these toppings in a burger by uttering those same magic words.

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Now discover the most iconic fast food items in history

Last updated by Luke Paton.

The very best fast food secret menu items, ranked