Folks, there is beef, and then there is beef. The beef between Elon Musk and Mark Zuckerberg is one to savour, to contemplate, to remember; a feud between two men worth billions, but with the emotional dimension of toddlers fighting over who gets to drive the Cozy Coupe.

It all began back in September 2016, when Zuckerberg’s $200 million Internet.org satellite exploded in a pre-launch test fire accident on one of Musk’s rockets. In response, Zuckerberg wrote in a Facebook post that he was “deeply disappointed” that “SpaceX’s launch failure destroyed our satellite,” a tone so passive aggressive that if it had come from a roommate I would probably start locking my door at night.

Nearly a year later, in a public Facebook Live stream, the Facebook CEO not-so-subtly took a jab at Musk’s anxiety toward artificial intelligence. Musk previously said that AI poses an existential threat to the human race—a viewpoint that Zuckerberg characterized as “pretty irresponsible.” While casually BBQing a brisket in his San Francisco backyard, Zuckerberg said he had “pretty strong opinions on this. I am optimistic.”

“And I think people who are naysayers and try to drum up these doomsday scenarios—I just, I don't understand it. It's really negative and in some ways I actually think it is pretty irresponsible.” Facebook uses machine learning in myriad ways, including scanning posts to identify potentially suicidal users.

Not one to be owned without a fight, Musk took to Twitter the next day, and savagely dismissed Zuckerberg’s comments. “I've talked to Mark about this. His understanding of the subject is limited,” Musk tweeted.

On Friday, the feud reached its most heated moment since Zuckerberg’s satellite blew up on Musk’s rocket. In response to a tweet by WhatsApp co-founder Brian Acton encouraging his followers to delete Facebook in protest of how the social network handles user data, Musk wrote, “What’s Facebook?” That alone, I think we can all agree, is a pretty solid own. But then, he took it to the next level: Musk pledged to delete his and his companies’ Facebook pages and then actually did it.

Musk then went in on the old satellite grudge, tweeting, “Yeah, my fault for being an idiot. We did give them a free launch to make up for it and I think they had some insurance.”

Zuckerberg has not yet, to our knowledge, released a diss track in response.

It remains to be seen whether Musk will delete his Instagram account as well. Facebook owns Instagram, and today he tweeted that Facebook’s “influence is slowly creeping in.” Musk posts on the reg—probably more than any other tech CEO, sharing everything from photos of ex-girlfriends to his recent trip to Jordan.

Picking a favourite between Musk and Zuckerberg is a no-win scenario; Musk is successfully privatizing part of humanity’s collective journey into outer space for his own benefit, and Zuckerberg has facilitated vast amount of sensitive information being scooped up and used by unknown parties for unknown and often surprising purposes, as this week’s Cambridge Analytica saga showed.