A deeply personal song Hetfield never intended for the band. He initially feared fans would "throw up" at its softness, but it became one of their most enduring hits. "Don’t Tread on Me":
Released on , Metallica (commonly called The Black Album ) marked a sonic shift for the band – slower, heavier, and more refined than their thrash roots. Produced by Bob Rock , it became their best-selling album (over 30 million copies worldwide).