Elon Musk has taken it upon himself to act as the canary in the coal mine that is the artificial intelligence world for some time now. The SpaceX, Tesla, Boring Company founder and CEO believes that AI is part of the future but also that there needs to be regulation around it, now.

Early Tuesday morning on the East Coast, Musk tweeted an article from Venture Beat about a future with an AI god. More specifically, the AI god that former Uber engineer, Anthony Levandowski is planning to develop. Musk tweeted the article and wrote “On the list of people who should absolutely *not* be allowed to develop digital superintelligence…”

He gave no further information about why Levandowski was one of the people who he thought should not be allowed to develop such an AI. But the two have been in conflict before. Text messages between former Uber CEO and Levandowski, the engineer who was working on self-driving technologies at Uber at the time, show that the two discussed Musk. Levandowski allegedly said, “we’ve got to start calling Elon on his shit.”

Tesla didn’t publicly respond to these messages. Musk’s first response might have something to do with the somewhat hostile history he and Levandowski have, but his criticism of AI technologies are not specific to the former Uber employee. Levandowski isn’t the first person Musk has criticized when it comes to AI. Musk also called Facebook co-founder Mark Zuckerberg's understanding of AI “limited” over the summer. This was prompted by a Facebook live video Zuckerberg recorded in the backyard of his Palo Alto home while smoking meat in which he called Musk’s AI warnings “irresponsible.

Musk himself has been working on AI technologies, most prominently with the self-driving technology that his Tesla vehicles are equipped with. Just a few days ago he tweeted that the vehicles would not only be able to drive passengers to their destinations in the future, the cars would actually predict where passengers want to go as well.

In June, Musk tweeted that in his opinion, he believes that AI will surpass humans sometime around 2030 to 2040, though he hoped that he was wrong. During a conference in 2016 he said he believes that humans could end up left behind by AI if they don’t adapt. This is where he proposed the integration of AI along with the human race via a neural lace, something his company Neuralink could potentially develop. But without this integration and adaptation, Musk believes AI could end up taking over life as we know it.

While advocating for this change, he also emphasizes the need for regulation. During a conference with governors from around the country this summer Musk called AI the “biggest risk that we face as a civilization.” He then advised the governors to first learn more about AI and its development and then bring regulations to law to help slow down the creation of AI and ensure public safety. He wrapped up by saying, “I think once there is awareness people will be extremely afraid, as they should be.”