The sound is associated with the zombie enemies in Half-Life 2, Valve's 2004 first-person shooter. Zombie audio from the game became widely recognized among PC players and later spread through meme edits, machinima and short gaming compilations online. People still use it because the voice is distinctive, low fidelity in a memorable way, and instantly readable as both horror and comedy. Its staying power comes from that mix of classic game nostalgia and the uncomfortable human-like groan that makes even brief clips feel uncanny.