The book reveals that such fights were a common occurrence when the brothers worked at the same office.
Walter Isaacson, whose biography of Elon Musk was recently released, revealed that the billionaire once had to be rushed to the emergency room after his brother Kimbal Musk tore a piece of flesh from his arm during a fight, New York Post reported.
Kimbal Musk bit his brother because he thought Elon Musk was about to punch him in the face, the book said. The incident took place when both of them were looking after their startup-Zip2-more than 20 years ago. As a result of the incident, Elon had to be taken to the hospital where he received stitches and a tetanus shot.
“The brothers often had ‘rolling-on-the-office-floor fights' while they worked together at Zip2, their company that provided city guides to newspapers. Because Zip2 didn't have private offices, other staff had to watch the two fight,” reads an excerpt from Isaacson's book, reported Business Insider.
The book reveals that such fights were a common occurrence when the brothers worked at the same office.
"When we had intense stress, we just didn't notice anyone else," Kimbal Musk was quoted telling Isaacson. He also said that even though he loved his brother ''very, very much'', working with him was 'hard'.
The Musk brothers ran Zip2 until they sold the company to Compaq Computer in 1999 for $305 million. Elon Musk received $22 million from the sale while Kimbal Musk earned $15 million.
The siblings also used to fight a lot when they were kids and fell out over small things. "Growing up in South Africa, fighting was normal. It was part of the culture," Elon Musk was quoted telling Isaacson.
The book also talks about how Kimbal used to feel embarrassed by Elon's posts on X and how he decided to unfollow his brother on the platform when his posts became "too nerve-racking" for him.
The biographer spent three years chasing Elon Musk to complete his book.