“Ozzy Osbourne, born 1948. Died, whenever. He bit the head off a bat.”

Although Mr. Osbourne styled himself as a menacing banshee, offstage he was a genial homebody. Devoted fans had known this at least since 1988, when the Penelope Spheeris documentary “The Decline of Western Civilization Part II: The Metal Years” featured a gregarious Mr. Osbourne making scrambled eggs while wearing a leopard-print kimono.

the group embraced the logic that people paid to be scared at horror movies, and the young musicians renamed themselves Black Sabbath, inspired by a Boris Karloff film with that title.