What symbol inspired the snake on the cover of Metallica's 1991 album Metallica?

The snake on the cover of Metallica's 1991 album Metallica was inspired by the Gadsden flag. The snake appears in the lower-right area of the nearly black cover design.

The Gadsden flag is an American historical flag featuring a coiled rattlesnake and the motto "Don't Tread on Me." Metallica's album also contains a song titled "Don't Tread on Me," creating a direct connection between the artwork, the track list, and the historical image.

The cover's restrained design helped produce the album's famous nickname, The Black Album. The band's logo appears in the upper-left corner, while the snake and logo were initially embossed so subtly that they nearly disappeared into the black background.

The image should not be confused with the Union Jack, the Confederate flag, or a pirate flag. The cover uses a modernized, minimalist presentation rather than reproducing the Gadsden flag in full. Later editions made the emblems more visible with dark-gray treatment.