In a video that has since gone viral, the 26-year-old handed over the keys to a Tesla Model S, and she later had more harsh words for the world's richest man.
"I need to make up for the 60 percent cut that Elon made to our son's child support," she told Daily Mail in the video.
When asked if it was Musk being vindictive, St. Clair elaborated that it's "his modus operandi when women speak out ... You can check out the stocks. I am not the only one cleaning up his messes, she added before the Tesla was towed away on a flatbed.
Musk responded to the video, posted by right-wing reporter Laura Loomer, stating that he doesn't know if the child is his, but he is willing to find out. "No court order is needed."
He added that "despite not knowing for sure, I have given Ashley $2.5M and am sending her $500k/year."
The two had previously shared barbs, and she went public earlier this year alleging that Musk was the father of her 8-month-old boy.
That move reportedly led to the SpaceX founder to begin cutting child support payments, which Musk has denied.
Paternity and custody lawsuits have reportedly been filed in New York, though St. Clair said that she and Musk have not spoken since Thursday, Feb. 13.
The entire Daily Mail report can be found here.
Click here to follow Daily Voice Fort Lee and receive free news updates.