This song was originally written by original Metallica member and Megadeth founder Dave Mustaine. The lyrics were originally about teen sexual frustration, as seen in Megadeth’s recording of Mustaine’s version, “Mechanix.” Later, it was rewritten to be about The Four Horsemen of the Apocalypse.

According to Joel McIver’s biography Justice for All: The Truth about Metallica, the melodic bridge did not appear in the original, pre-Kill ‘Em All version of the song – it was written by bassist Cliff Burton and captured during these recording sessions.