The sound comes from Valve's Index VR system, where controllers power down with a short electronic tone when they are switched off or run out of battery. In VRChat, where players spend long sessions talking, dancing and roleplaying in virtual worlds, that familiar tone became a handy tool for pranks. Creators began clipping the shutdown noise and dropping it into videos and live sessions to imitate a sudden disconnect, and it spread through VR and meme communities because almost every Index owner recognises it instantly.