The Boeing 737 overspeed warning, often called the clacker, is a real cockpit alert triggered when airspeed exceeds Vmo or Mach limits. Flight simulators like Microsoft Flight Simulator and X-Plane reproduce the sound faithfully, which helped it spread beyond aviation training into YouTube edits and meme videos. Pilots and simmers instantly recognize the rapid clicking as a cue to reduce thrust and pitch up. Online, creators borrow that realism to make fake emergencies feel convincing and to punctuate any scene where speed gets out of hand.