Elon Musk’s not-so-friendly bid to buy OpenAI for $97.4 billion caught many in the tech world by surprise, but it’s just the latest shot in a yearslong battle between Musk and Sam Altman, who co-founded OpenAI together nearly 10 years ago.

The OpenAI CEO quickly rejected the deal on Musk’s X platform, saying, “no thank you but we will buy Twitter for $9.74 billion if you want.”

In an interview with Bloomberg, Altman says OpenAI is “not for sale” and the bid is the latest of “tactics, many, many lawsuits, all sorts of other crazy stuff, now this” for the “competitor” Musk to “slow us down.