The chirp comes from standard household smoke alarms, which use a loud piezoelectric beeper to signal a low battery or fault, usually with one short beep every thirty to sixty seconds. The pattern is designed to be impossible to ignore but easy to localise badly, which is why it became a running joke online. Clips of the beep spread through prank videos, streams and soundboards, where a single unseen chirp can send an entire room or chat looking for the detector, and it remains popular for that instant reaction.