In an expanded version of a previous lawsuit, Musk called OpenAI a “market-paralyzing gorgon,” the Wall Street Journal reported. He’s also taken to calling Altman “Swindly Sam,” a mocking nickname in the style of his new closest ally, President-elect Donald Trump. 

Musk and Altman have had a tense relationship since the Tesla CEO left OpenAI in 2018. As OpenAI puts it, Musk said at the time that the team’s “probability of success was zero, and that he planned to build an AGI [artificial general intelligence] competitor within Tesla.” 

A year before he left, OpenAI had rejected Musk’s offer to take control of the company, despite his being the biggest source of its funding. Since then, Musk has founded his own AI company, xAI. 

Musk in March sued Altman and ChatGPT-maker OpenAI for allegedly violating the nonprofit principles the company was founded on, in part because it struck a multibillion-dollar agreement with Microsoft. 

OpenAI has since switched to a “capped” for-profit enterprise. Musk asked a judge Friday to prevent OpenAI’s efforts to become a fully for-profit business, CNBC reported.

After a friendly chat with Altman around a firepit at a technology conference in Montana, Musk dropped his original lawsuit against OpenAI, the Journal reported, but he refiled it in August. 

OpenAI did not immediately respond to Fortune’s request for comment.

Now the pair’s relationship is seemingly at an all-time low just as Musk has garnered major influence with Trump, which could affect OpenAI’s prospects in terms of regulation. As one of the former president’s biggest funders during the 2024 election cycle, Musk has gained significant influence with Trump.

The Tesla CEO was named co-head of the Department of Government Efficiency, which will advise the government on how to drastically cut spending. Musk has even sat in on calls with foreign leaders and backed allies for regulator positions that oversee his companies.

While Altman has tried to make friendly overtures to the incoming Trump administration through contacts such as Trump’s son-in-law Jared Kushner and his brother, Josh Kushner, whose VC firm, Thrive Capital, has invested in OpenAI, his bad relationship with Musk complicates things, the Journal reported.

Musk is known for his public spats with fellow billionaires, including Amazon chairman Jeff Bezos and Microsoft cofounder Bill Gates. Last year, he even challenged Meta CEO Mark Zuckerberg to a cage fight. 

As for Altman, Musk has not held back his thoughts.

“I don’t trust OpenAI. I don’t trust Sam Altman. And I don’t think we ought to have the most powerful AI in the world controlled by someone who is not trustworthy,” he told former Fox host Tucker Carlson in October.