Enter Sandman was released by Metallica in 1991 as the lead single from their self-titled album, often called The Black Album. Its ominous riff and lullaby-inspired lyrics helped it become one of the band's signature songs and a staple of rock radio. The track later became famous as an entrance theme in wrestling and baseball, and at college football games, reinforcing its link to dramatic arrivals. Short clips of the opening continue to circulate online because a few seconds are enough for most listeners to recognise the song instantly.