Law & Order premiered on NBC in 1990, created by Dick Wolf, and its distinctive dun dun sound was composed by Mike Post to mark scene transitions between police investigation and courtroom trial. The two-note sting became one of television's most recognizable audio cues, instantly signaling a shift in the story. As the franchise expanded into multiple spin-offs, the sound spread beyond TV into parodies, trailers and social media edits, where creators borrowed its serious tone to make trivial reveals feel like major legal turning points.