We asked the BuzzFeed Community for their favorite In-N-Out secret menu items. Here are their genius hacks.
1. The 4x4

What it is: A regular In-N-Out burger, but it's stacked with four beef patties and four slices of cheese. Otherwise known as "heaven."
2. The Flying Dutchman

What it is: This is basically a grilled cheese, but it's got beef patties instead of bread. Feeling like a daredevil? Add some fries to the middle as well.
—Melody Lai, Facebook
3. Grilled Cheese

What it is: Your typical burger, sans beef. Don't be scared to go Animal Style on this one.
—Darrah Jones, Facebook
4. Neapolitan Shake

What it is: The perfect combination of strawberry, chocolate, and vanilla ice cream, all in shake form.
—Gavin Rose, Facebook
5. Chopped Chilies

What it is: A glorious burger (or fries) topped with chili peppers.
—ohm
6. Roadkill Fries

What it is: Animal Style fries with a Flying Dutchman on top. Not bad, In-N-Out. Not bad at all.
7. Root Beer Float

What it is: A glorious combination of vanilla ice cream and root beer. Drink up.
8. Fries Well-Done

What it is: In-N-Out does "light-well" and "well-done" fries. If you want your fries a little crispier, they'll keep them in the fryer for a few extra minutes.
9. Protein-Style

What it is: Your average burger with the buns swapped out for lettuce.
10. Animal-Style Fries

What it is: French fries topped with gooey cheese, grilled onions, and In-N-Out's special sauce.
11. Mustard-grilled Patty

What it is: This may look like a regular burger, but the beef patty is actually grilled with mustard before it even hits the bun. More flavor in every bite.
12. Lemon-Up

What it is: Lemonade and 7-Up, perfectly blended together. If you're feeling wild, mix it with pink lemonade.
13. Cheese Fries

What it is: Melted cheese that's spooned directly onto crispy fries. You can't go wrong here.
14. Whole Grilled Onion

What it is: It's exactly what it sounds like: whole grilled onions on top of a perfectly grilled burger.
15. Doggy-Style

What it is: A protein-style grilled cheese with fries inside the sandwich. So much happening, so worth it. #LastMealBeforeIDie.
16. And Chili Cheese Fries

What it is: This is super secret, and the employees have to be willing. But legend has it, if you ask for this three times and are denied the first two times, on the third you will receive. WORTH IT.