A prank in which one is enticed into watching a screamer, which is a game or picture that is rigged to emit a loud scream, usually accompanied by a scary picture. To be targeted is to be scream rolled. The term is a derivative of the infamous rick roll prank.
My friend emailed me a picture which had instructions to observe carefully for something strange in it. After several minutes of looking, a loud scream sounded, and a horrible face popped up on the screen. I'd been scream rolled!