If the camera effect on show during Billie Eilish's performance on 'SNL' looks familiar to you from the likes of 'Inception', you're correct.
The process involves fixing a camera to a rotating set and then manually moving the entire set like a hamster's wheel. The camera, because it's stationary and rotates with the set, makes it seem like the movable object inside - Billie Eilish, in this case - is able to walk up walls.
The camera trick has been used countless times in the likes of '2001: A Space Odyssey', 'Poltergeist', 'Nightmare On Elm Street' and, more recently, 'Inception'. In that instance, a huge set was built that was nearly 30 feet wide and 120 feet long to replicate a hotel corridor.
This time around, however, it's Billie Eilish on the 'SNL' soundstage with two stagehands rotating the set.
Take a look.