Don't Hang Up (2016)

Best friends, Sam and Brady have a lot of fun pranking people, in fact they have so much fun with it, they even started a YouTube prank channel together. However, one night while hanging out together, the two friends receive a phone call from a mysterious man, who does not think their pranks are anything to laugh at. He gives them only a single order: don't hang up. The man then subjects the duo to a night of pure terror. Who is this man and what does he want?