The Combine are the alien regime that rules Earth in Valve's Half-Life 2, and their soldiers speak in cold, robotic, heavily filtered voices. A laugh from one of them is therefore an oddity, which is why this short clip took off on soundboard sites and in gaming meme circles. Creators use it as a sinister taunt or a dark-comedy reaction, and the numbered title suggests it is one of several fan-captured variants floating around online. Two seconds of a machine laughing at you is hard to forget.