Enter Sandman is the opening track from Metallica's self-titled 1991 album, commonly known as the Black Album, and it became one of the band's most famous songs, regularly opening their live shows and appearing in films, games and sports arenas. Its simple, instantly recognisable riff helped it cross over from metal fans to mainstream audiences, and online creators later adopted short clips of it as shorthand for power and intimidation. That long life in stadiums and pop culture keeps the riff instantly familiar to new listeners.