The end-of-call sound comes from the telephone network itself: hanging up a mobile phone plays a short click followed by the dial tone that signals a dead line. As smartphones replaced landlines, the sound became a piece of shared audio memory, instantly recognisable even to people who rarely make calls. Online it circulates as a stock effect in prank calls, fake conversation skits and meme edits, where the click marks the exact moment someone gets shut down. Its staying power comes from that universal recognition.