Errol Musk denies berating his son after an attack at school put Elon Musk in hospital

• Elon Musk said his father once called him "worthless" after he was beaten up at school.
• Musk shared the experience in Walter Isaacson's new biography of Musk.

Elon Musk and his father, Errol Musk, are giving conflicting characterizations about the elder Musk's reaction to an attack at school that the two agree was severe enough to have put Elon Musk in the hospital.

The story was recounted in Walter Isaacson's new biography of Elon Musk, who's now the world's richest person. Setting up the incident, Isaacson wrote that Musk was often bullied in school because he was "the youngest and smallest student in his class," adding that it didn't help that Musk lacked the empathy and desire to win friends.

Isaacson then went on to describe an altercation in which a student who was playing with his friends bumped into Musk, prompting Musk to push him back and the two to exchange words. The boy and his friends later jumped Musk at recess, Isaacson wrote, and pushed him down a flight of concrete steps.

"They sat on him and just kept beating the shit out of him and kicking him in the head," Musk's brother, Kimbal Musk, who had been sitting with him, told Isaacson.

"When they got finished, I couldn't even recognize his face," he said. "It was such a swollen ball of flesh that you could barely see his eyes."

Isaacson wrote that while the beating had even required Musk to get corrective surgery in his nose decades after it happened, "the scars were minor compared to the emotional ones inflicted by his father," who while speaking with Isaacson for the book appeared to justify the attack on his son.

Errol Musk told Isaacson: "The boy had just lost his father to suicide and Elon had called him stupid. Elon had a tendency to call people stupid. How could I possibly blame that child?"

But the elder Musk's account differs from his sons' about what happened when Elon Musk came home from the hospital. The Musk brothers said Errol Musk lashed out at his son. "I had to stand for an hour as he yelled at me and called me an idiot and told me that I was just worthless," Elon Musk said.

Kimbal Musk described it to Isaacson as the worst memory of his life. "My father just lost it, went ballistic, as he often did," he said. "He had zero compassion."

The brothers no longer speak with their father. Elon Musk told Rolling Stone in 2017 that his father is "a terrible person."

"No, I did not berate Elon," Errol Musk told Insider in an email. "That is nonsense. Elon was in the hospital for a few days. It was not possible to do that nor would I have done that. I was shocked by the incident."

He added that the main boy involved was "much smaller than Elon," and that they were both about 12 or 13 years old.

Isaacson wrote that Errol Musk moved Elon Musk from a public school to a private academy, Pretoria Boys High School, after the attack. Errol Musk reiterated this to Insider, saying he "went to the expense of buying another house in another city to be able to put Elon and Kimbal in there."

Elon and Kimbal Musk's mother, Maye, divorced Errol Musk in 1979. In an interview with Harper's Bazaar, she described it as an abusive marriage.

Ex-girlfriend Grimes told Isaacson that Elon Musk's experience with his father has had an impact on future relationships.

"He associates love with being mean or abusive," she told Isaacson, "It's about his father and what he grew up with."

His first wife, Justine Wilson, whom he was married to from 2000 to 2008, told Isaacson that Musk would sometimes call her a "moron" or "idiot," which she associated with Errol Musk.