This sound comes from Five Nights at Freddy's 2, the 2014 horror game by Scott Cawthon. Players know it as the music box tune tied to the Puppet mechanic, which made the melody memorable far beyond the game itself. Over time, fans clipped the cue for YouTube videos, TikToks and short memes whenever they wanted a quick burst of creepy anticipation. It still gets used because the tune is instantly recognizable to FNAF fans and communicates danger in barely more than a second.