Far from being a gross act of rebellion, then, the bat ended up in Osbourne’s mouth due to a series of schoolboy dares and misunderstandings. And despite his tendency to milk the myth, even Osbourne has admitted it was stupid. A decade after the event, he described in a TV documentary just how painful those rabies jabs were. “I had one in each rear, one in each arm, and one in the top of my leg – and I had to have that every night. For anyone out there who thinks it’s ‘cool’… if you want to be a complete dick, try it,” the singer said. (In a show in Illinois six days after the Des Moines incident, Osbourne collapsed on stage due to illness caused by the shots.)

But none of this matters. What matters is the myth. And it goes to the heart of what rock music has always been about. Danny Goldberg is a music executive who was Led Zeppelin’s PR man in the Seventies and went on to manage Nirvana in the Nineties. “Regardless of the facts — and, yes, myth is more important than reality when it comes to these things — the story that Ozzy bit off the head off a bat added a dark mystique to his persona,” Goldberg tells me. “His career would have still have travelled on a successful arc because of his musical talent and charisma, but the bat story added a unique talking point that reinforced the image he had already created. It’s hard to imagine any summary of Ozzy’s career that wouldn’t include the incident.”

Musicians have to have their shtick, whether it’s Alice Cooper appearing on stage with a snake, Madonna constantly prodding the Catholic church or Jimi Hendrix setting fire to his guitar. A musician does something, that something becomes part of their image, the image becomes part of the marketing, and before you know it, the something and the musician are one and the same. 

It could even be something as small as Ed Sheeran’s effects pedal, Adele’s “cor blimey” stage patter or Slash from Guns N’ Roses’ trademark top hat: no concert would be complete without them. “Ozzy and the bat is the same as Alice Cooper and the snake. I’d go so far as to say that biting the bat took Ozzy Osbourne up to a completely new, if rather eccentric, level,” says Nick Stewart, the music manager and label boss who signed U2 to Island Records in 1980.