One of heavy metal’s defining tracks, “Iron Man” pairs Tony Iommi’s monolithic riff with Geezer Butler’s sci-fi lyric about a man who sees apocalypse in the future, returns transformed “into steel,” and brings about the destruction he foresaw. First appearing on Paranoid (1970), it later became a hit single (US #52, 1972) and a staple of the band’s legacy and popular culture.