You’ve seen it before: You’re watching a movie when all of a sudden everything seems to flip. Instead of watching the actor move through the world, suddenly it feels like it’s everything but the actor that’s moving—and it all feels like it’s rushing by. It’s a visual effect you can chalk up to the SnorriCam, a special device that mounts the camera directly on the actor’s body. Most often used to show a character in an altered state (whether due to drugs or trauma), the SnorriCam is named after two Icelandic filmmakers, Einar Snorri and Eidur Snorri (no relation). It was greatly popularized by Darren Aronofsky, especially through his early movies Pi (1998) and Requiem for a Dream (2000), but the use of such devices dates back to at least Martin Scorsese’s Mean Streets (1973) and John Frankenheimer’s Seconds (1966).