Unlike a quote from a film or show, this clip is a general naval sound effect built around the sonar ping listeners associate with submarines and sea warfare. Similar pings have been used for decades in war films, documentaries and games to signal a search happening beneath the surface, and the effect has become shorthand for hidden danger even when no ship is shown. Online, creators reuse long sonar recordings for submarine edits, naval battle montages and tense underwater scenes because the steady pulse needs little explanation.