What happens when Harry Potter gets lost in a train station?
That's the setup for this great little prank that excited the crowds in a New York train station. It's pretty amazing, especially given the reactions of the crowd.
We love the guy who tries to help by explaining Kings Cross station is in England, not New York.
This stroke of genius comes from Improv Everywhere, a comedy group who shot to fame for the "No Pants Subway Ride" tradition in New York, and the world-famous Food Court Musical video which probably set off the international obsessions with flash mobs.
They've been doing this for more than a decade, and this "movies in real life" is their latest series. You can check out their YouTube channel for more.