Left 4 Dead is Valve's cooperative zombie survival shooter, first released in 2008, and its short in-game cues have long circulated on soundboards as numbered clips. Sounds like this one are shared by players who recognise the game's audio instantly, then reused in gameplay videos, edits and memes for a quick hit of tension or comedy. Because the clip is under a second long, it travels easily between platforms and still works years later, especially for audiences who played the original co-op campaigns.