Tesla just unveiled its new "bulletproof" truck. During a test, its windows broke.

Tesla showed off its newest all-electric vehicle, Cybertruck, during an event in Los Angeles, but its unveiling on Thursday night didn't appear to go as planned. After the Tesla pickup truck was rolled out, the company's chief designer threw a metal ball to prove how tough it was –– except the demo failed spectacularly.

Tesla CEO Elon Musk told an audience the truck is "literally bulletproof" against small types of firearms. The truck's body withstood multiple strikes from a sledgehammer and the crowd cheered on. Musk then summoned design lead Franz Von Holzhausen to try and smash the Cybertruck's "armor glass."

Video shows Von Holzhausen throwing a metal ball and appearing to look shocked when the driver's seat window was completely shattered."Oh my f----ing god," Musk said. "Well...maybe that was a little too hard. It didn't go through." 

Von Holzhausen tried a passenger's side window and it had the same exact result. "Not bad," Musk said, "There's room for improvement." 

"We threw wrenches, we threw everything, even literally the kitchen sink at the glass and it didn't break," he added. "For some weird reason, it broke now. I don't know why. We will fix it in post."

CBS News reached out to Tesla to ask about the the windows breaking. Social media users couldn't help but poke fun at Tesla after this gaffe. 

"Imagine thinking your Tesla truck is bulletproof because the company said it has Tesla Armor Glass, you didn't see this video before you bought it, and some hipster breaks your window with a little rock," one Twitter user said. 

The 250-plus-mile Cybertruck will cost $39,900. The midrange Cybertruck tacks on an extra $10,000, while the top-range, "tri-motor" variant comes in at $69,900. 

In:
• Tesla
• Elon Musk