Deltarune is an episodic role-playing game by Toby Fox, first released in 2018 as a follow-up to Undertale, and its eerie, musical sound design has made many of its short effects popular outside the game itself. The hypnosis sound comes from that world, where strange music and shifting tones help sell moments of magic, confusion, and control. Once clips began circulating on soundboards and in short video edits, creators started using it on its own, detached from the original scene, as a quick shorthand for being hypnotised, distracted, or put into a trance.