Here is the best prank you can play on your friend while he's testing an Oculus Rift in a Russian shopping mall:
View this video on YouTube
Just when the video of a rollercoaster reached the top, his friend pushes him:
And he freaks out.
And keeps freaking out...
And continues to freak out until people come scrape him off the floor.
H/t Reddit
One thing: Something about this seems like it MIGHT be staged, but we're not sure. It's funny either way.