The Twilight Zone was an American anthology television series created by Rod Serling that first aired in 1959, with each episode presenting a standalone story with a twist ending. Its distinctive theme music, composed by Marius Constant, was introduced in the second season and quickly became inseparable from the show itself. As reruns, references and parodies spread, the theme became cultural shorthand for anything strange, unexplained or suddenly uncanny, which is why creators still use it today to signal that reality has just taken an odd turn.