Which Metallica song begins with a melody from West Side Story?

Metallica's “Don't Tread on Me” begins with a melody from West Side Story. Its instrumental introduction uses an eight-bar phrase from “America,” a song composed by Leonard Bernstein for the musical.

The track appears on Metallica's The Black Album and takes its title from the motto on the Gadsden flag. That connection explains why the song's subject and the album cover's snake image are closely related.

The quotation is an interpolation rather than a separate cover version of the complete musical number. Metallica built the rest of the song around its own heavy-metal arrangement, lyrics, and rhythmic guitar work.

“Don't Tread on Me” was issued to rock radio shortly after the album's release, but it was not one of the five commercial singles. It was also not performed live until the band's European tour in 2012, during the Black Album anniversary period.