Enemy Duck Fly Flap comes from R.E.P.O., the co-op horror game by Semiwork that launched in early access in 2025. The duck is one of its deceptive enemies, harmless looking until it turns aggressive and takes flight during encounters. Clips of those sudden attacks spread quickly through gameplay videos and streams, where players learned to fear the small flapping cue. Editors later isolated the flap as a standalone effect for memes and shorts, and it remains popular because such a brief, recognisable cue instantly signals a cute threat going wrong.