Deltarune is Toby Fox's episodic role-playing game that follows Undertale, with its first chapter released in 2018 and later chapters expanding the story of Kris, Susie and Ralsei. Dark Fountains sit at the heart of that story, opening the Dark Worlds the heroes explore, so the music tied to their creation quickly became a recognisable shorthand for the game itself. Fans have since reused the cue in edits, streams and lore videos, keeping it popular as new chapters arrive and new players discover the series.