Which band inspired the main guitar riff for Metallica's song Enter Sandman?

Soundgarden inspired the main guitar riff for Metallica's song Enter Sandman.

Kirk Hammett wrote the initial guitar idea after listening to Soundgarden's 1989 album Louder Than Love. The original riff was two bars long, and Lars Ulrich suggested changing its repetition pattern to create the distinctive opening figure.

The instrumental parts developed quickly, but James Hetfield took longer to write the vocal melody and lyrics. The final lyrics center on a child's nightmares, including bedtime imagery and a prayer, giving the song a darker meaning beneath its highly memorable groove.

Enter Sandman became the first song written for the album and ultimately served as its lead single and opening track. Its creation illustrates how the record combined ideas from contemporary alternative rock with Metallica's own heavy-metal approach.