The sound comes from the S.T.A.L.K.E.R. first person shooter series by GSC Game World, beginning with Shadow of Chernobyl in 2007. Set in the Chernobyl Exclusion Zone, the games fill the area with mutated wildlife, and the Flesh is one of the most common mutants, a deformed swine like creature that attacks in groups. Players learned to recognise its short attack noise during close encounters. Clips of that hit later spread to soundboards and editing packs, where it is reused outside the game as a generic mutant ambush and jumpscare effect.