Race car driver and “Mythbusters” star Jessi Combs was killed in an attempt to break her own land-speed record. She was 36.

“The Discovery and MotorTrend family is deeply saddened to learn of the tragic passing of Jessi Combs,” Discovery said in a statement to Variety. “She was a friend and colleague, an icon in the industry, and an undeniable force of nature who left an indelible mark on the car world. Our thoughts are with her family and loved ones.”

Combs earned the title of “the fastest woman on four wheels” after hitting 398 miles per hour in 2013 in the jet-powered North American Eagle Supersonic Speed Challenger. In the fatal car crash, she was aiming for 619 miles per hour on a dry lake bed in the Alvord Desert in Oregon, according to Autoblog. Combs posted an Instagram picture three days ago ahead of the attempt.

Combs was one of the hosts of “Mythbusters,” joining in 2009. She was filling in for fellow host Kari Byron, who briefly left the show to give birth to her first child. Combs was also a co-host of “The List” and hosted “Overhaulin’,” “Extreme 4×4” and “All Girls Garage.” In 2014, Combs became the first women to place at any Ultra4 event.

Combs’ team member Terry Madden shared a montage of the driver on Instagram. Madden wrote, “She was truly my unicorn and I enjoyed every single minute that I had with her.”