Enter Sandman was released by Metallica in 1991 as the opening track and lead single from their self-titled fifth album, often called the Black Album. The song quickly became one of the band's signature tracks and a staple of rock radio, sports arenas and film soundtracks. Its opening riff is now instantly associated with Metallica even for listeners who do not follow heavy metal. Decades later, creators still borrow the intro because it signals intensity and confidence in seconds, making it a reliable shorthand for a big moment.