Tesla co-founder and CEO Elon Musk stands in front of the newly unveiled all-electric battery-powered Tesla’s Cybertruck at Tesla Design Center in Hawthorne, California on November 21, 2019. (Photo by FREDERIC J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)

It was the moment that sparked a mass of memes and unwanted press. This week, Elon Musk unveiled the long-awaited Tesla Cybertruck dressed in a futuristic exterior and supposedly bullet-proof windows. During the event, the lead designer of Tesla, Franz von Holzhausen, was invited to throw a metal ball at the window to illustrate its strength. And well, everyone knows what happened next.

Instead of miraculously bouncing off the glass, it shattered and the ball simply rolled away. For Tesla, it was far from ideal and pretty embarrassing whether it was a PR stunt or not. But taking to Twitter to do damage control – both literally and figuratively – Musk has explained why it happened, despite testing beforehand.

According to the entrepreneur, the base of the glass was cracked beforehand by a previous demonstration when von Holzhausen swung a sledgehammer at the Cybertruck’s body. This was believed to have diminish the structural integrity of the window, allowing the window to smash. To prove it had in fact worked in the past, Musk also posted a video of testing before the event, shortly after the blunder – just to further instil customer satisfaction.