That thingy that records it?
Not exactly, it's a hypothesis for why certain supernatural sightings and "hauntings" occur. Apparently, at 18.9 Hz of sound frequency, even tho essentially all humans can't hear that frequency, you can still "feel" it. The vibration can apparently cause slight distortions in the corner of your eye and a sense of uneasiness. But Mythbusters apparently disproved it was a thing.