Joshua Achiam, OpenAI's chief futurist, testified in the Musk v. Altman trial. Bloomberg/Getty Images

OpenAI exec Joshua Achiam testified about a "tense exchange" he had with Elon Musk in 2018.

Musk, Achiam told the jury in the Musk v. Altman trial, called him a "jackass."

The two clashed over AI safety, and Achiam's colleagues later gifted him a gold "jackass" trophy.

An OpenAI executive told a federal jury Wednesday how Elon Musk once called him a "jackass" during a heated clash over AI safety.

Joshua Achiam, OpenAI's chief futurist, recalled the "pretty tense exchange" during testimony in the California civil trial between Musk and OpenAI CEO Sam Altman .

"He snapped and called me a jackass," Achiam testified.

Achiam said that around 50 to 60 employees had gathered during a February 2018 company all-hands meeting for a question-and-answer session ahead of Musk's planned departure from the startup he cofounded with Altman.

According to Achiam, then a research scientist at OpenAI, Musk said he was…