Law and Order is an American police procedural and legal drama created by Dick Wolf that first aired on NBC in 1990 and became one of television's longest-running series. Its short two-note transition sound, often written as dun dun, plays between scenes to signal a change of location or time, and audiences heard it thousands of times over decades of reruns. As clips spread online, creators lifted that brief sting out of context, using it as shorthand for drama, guilt or a sudden twist, which is why it still works instantly even for viewers who have never watched a full episode.