"Master of Puppets" is a thrash metal song by American metal band Metallica, released on July 2, 1986 as the sole single from the album of the same name. It was also issued as a promotional single in the US by Elektra Records.
The song was recorded during October–December, 1985 at Sweet Silence Studios in Copenhagen, Denmark.
The song was bassist Cliff Burton's favorite one on the album, as he said when it was released. From Wikipedia
