The Monkey Style myth all started in 2013, when a hoax video went viral in which someone ordered a burger topped with Animal Style fries. But In-N-Out famously has an extremely simple, limited menu, and they're not going to change it for an internet myth. "[In-N-Out] tries to stay as true to the original menu as possible," the former employee said.
And while it may not be a real item on the secret menu, that doesn't mean you can't get your burger topped with saucy fried potatoes. No one will stop you from ordering the two items separately and then combining them together (USA! USA!).