The guitar riff on this song is considered one of the most famous in rock history, and it is what the entire song was written around. And no, it’s not related to the Marvel character, who was created eight years earlier in 1963.

Via Time:

The alarming, dissonant guitar groan that kicks off “Iron Man,” eventually cohering into a primal five-note riff, struck lead singer Ozzy Osbourne as evoking “a big iron bloke walking about.”