The sound comes from the Warhammer 40,000 universe, tagged with Dawn of War, the real-time strategy series where Space Marines fight as heavily armoured super-soldiers. When a unit is killed in those games, a short death cry plays over the battlefield noise, and players began ripping and sharing individual clips for use outside the game. Because the cry is only about a second long and instantly reads as a death, it works well in memes, edits and streams, where a single sound can replace a whole explanation of failure.