Which Black Sabbath song was written for the 1981 animated film 'Heavy Metal'?

Which Black Sabbath song was written for the 1981 animated film Heavy Metal? The song was “The Mob Rules.” Black Sabbath recorded it for the film’s soundtrack during the band’s Ronnie James Dio era.

“The Mob Rules” was the first new recording Black Sabbath made after 1980’s Heaven and Hell. The lineup featured Dio on vocals, Tony Iommi on guitar, Geezer Butler on bass, and Vinny Appice on drums. The track was recorded at Tittenhurst Park, John Lennon’s former home in England, which was then associated with Ringo Starr’s recording facilities.

The song later became the title track of Black Sabbath’s tenth studio album, Mob Rules, released in 1981. The version heard in Heavy Metal is an alternate take or mix, so the film soundtrack and album versions are not identical. The related instrumental “E5150” also appears in the film, but it is not the song the question asks for.

Heavy Metal was a Canadian adult animated science-fiction anthology directed by Gerald Potterton. Its mix of animation and hard rock helped make “The Mob Rules” especially memorable to listeners who first encountered it through the movie.