The cardiac sensor is a gadget from the tactical shooter Rainbow Six Siege that detects nearby heartbeats, and its deployment sound became a recognisable cue for players tracking enemies through walls. Streamer Jynxzi, known for his energetic Rainbow Six Siege broadcasts, helped turn the short ping into a meme sound through repeated use in his clips and edits. Fans now reuse it outside matches to signal that someone has been spotted, keeping it popular in gaming montages and short-form reaction videos.