"And people said you knew nothing about cars," Musk's mother wrote in a tweet, hashtagging it "1995" and "Found This Photo."
Her son immediately made the connection to the embarrassing public introduction of Tesla's Cybertruck, where a Tesla designer threw a metal ball at its supposedly unbreakable windows -- breaking them.
Musk noted that, in his pre-billionaire days, he couldn't afford to pay for a mechanic to fix his car, so he did it himself with junkyard parts. "Ironically, that's me replacing broken side window glass," he acknowledged. "The circle is complete lol."
Musk went on to say that the car was a 1978 BMW 320i that he bought in 1993 for $1,400.
"I hotrodded it by jamming in a 5 speed transmission from a later model I found in a Philly junkyard when the 4 speed transmission failed," Musk said. He noted that he was repairing the window because thieves had broken in and stolen the radio, "which was worth maybe $20."