This sound comes from Undertale, the 2015 indie RPG created by Toby Fox. The game's dialogue uses small character-like beeps instead of full voice acting, and that default talking sound became recognizable far beyond the game itself. It spread through meme edits, fan animations and short gaming clips where creators wanted instant RPG dialogue vibes without recording speech. It is still popular because a single beep immediately signals retro humor, choice-based conversations and the distinct feel of Undertale's presentation.