What flag inspired the snake pictured on Metallica's 1991 album Metallica?

The snake on Metallica's 1991 album cover was derived from the Gadsden flag.

The cover places Metallica's angled logo in the upper-left corner and a coiled snake in the lower-right. The snake's imagery comes from the historic American flag associated with the motto “Don't Tread on Me,” which also became the title of one of the album's songs.

For the initial release, the logo and snake were embossed so subtly against the black background that they were difficult to see. This design helped create the nickname The Black Album, even though the official album title is simply Metallica. Later editions used dark-gray elements that stand out more clearly.

The cover is sometimes mistaken for a generic snake illustration or linked to other American flags. Its specific source is the Gadsden flag, while the album's broader visual identity comes from the nearly black presentation and minimal contrast.