Sam Altman filed a countersuit against his OpenAI co-founder Elon Musk on Wednesday, claiming the Tesla CEO “tried every tool available to harm” the artificial intelligence company when it succeeded following his departure.

Altman’s countersuit stems from a federal lawsuit filed by Musk last year that accuses Altman of diverging from OpenAI’s original nonprofit mission by partnering with Microsoft and keeping its advanced tech for private consumers.

The artificial intelligence company said in a post on X (which Musk owns) that it countersued Musk to end his “bad-faith tactics to slow down OpenAI and seize control of the leading AI innovations for his personal benefit.”

Attorneys representing Musk in this case did not immediately respond to a HuffPost request for a comment.

Altman and Musk co-founded OpenAI in 2015, along with Greg Brockman and Ilya Sutskeveralong, as a nonprofit lab. Musk abandoned the company three years later, after the rest of the board “refused to bow to Musk’s demands for control of the enterprise,” according to Altman’s counterclaim. When Musk quit, he declared OpenAI would fail without him, the countersuit said.

OpenAI launched ChatGPT in 2022, an achievement Altman’s suit says “Musk had nothing to do with.” As the company continued to grow, Musk was left on the “sidelines” and launched a “relentless” campaign against OpenAI, the suit claims.

“Musk could not tolerate seeing such success for an enterprise he had abandoned and declared doomed,” Altman’s countersuit read. “He made it his project to take down OpenAI, and to build a direct competitor that would seize the technological lead — not for humanity but for Elon Musk.”

Musk did everything he could to harm the company they co-founded, the countersuit claims.

Founded as a nonprofit, OpenAI now operates as a partnership between its original nonprofit and a capped profit subsidiary that raises “the capital for our mission,” according to the company’s website.

Musk’s attacks have intensified in recent months, according to the countersuit, after OpenAI announced potential plans to turn the “existing for-profit entity under the nonprofit OpenAI, Inc” into a public benefit corporation.

“Through press attacks, malicious campaigns broadcast to Musk’s more than 200 million followers on the social media platform he controls, a pretextual demand for corporate records, harassing legal claims, and a sham bid for OpenAI’s assets, Musk has tried every tool available to harm OpenAI,” the countersuit read.

In one example, Altman’s lawsuit alleged that Musk has “falsely and repeatedly claimed” that OpenAI was restructuring the entire company from a nonprofit to a for-profit entity.

The company addressed Musk’s claims publicly on Wednesday too, saying in a post on X that Musk has “been spreading false information about us.”