Elon Musk was left dumbfounded Thursday night after a botched test of Tesla’s first “bulletproof” electric pickup truck left its windows smashed up. The red-faced Tesla CEO tried to show off the durability of the Cybertruck’s “armor glass” windows by having chief designer Franz von Holzhausen throw a metal ball at them. Things went south immediately as the so-called armored glass was smashed by the metal ball during the live demonstration.

“Oh my f—ing God,” Musk muttered onstage. “Well, maybe that was a little too hard.”