R.E.P.O. is a physics based co-op horror game developed by Semiwork and released in early access in 2025, where teams recover valuables while avoiding roaming monsters. The duck, known in game as the Apex Predator, looks like a harmless follower but transforms when handled or damaged, turning a silly encounter into a panic moment. Clips of players accidentally triggering it spread quickly through gameplay videos and streams, and its looping flight sound became a shorthand for that danger hiding behind something cute.