The 6 AM sound comes from the original Five Nights at Freddy's, released in 2014, where it plays when the player survives a night until morning. Because the game became hugely popular on YouTube and in horror gaming culture, this brief victory cue spread far beyond the series. It is still widely used in meme edits, gaming montages and reaction videos because the sound instantly communicates tension ending in relief, even for people who only know it from clips and compilations.