Elon Musk joined the #DeleteFacebook movement on Friday, taking down official pages for two of his companies, Tesla and SpaceX, after he learned – apparently for the first time – that the pages existed.

The billionaire chief executive engaged in some light-hearted Twitter trolling on Friday morning, responding to a tweet from the WhatsApp co-founder Brian Acton, which urged people to delete the social network with the query: “What’s Facebook?”

What’s Facebook? — Elon Musk (@elonmusk) March 23, 2018

When a Twitter user brought up the fact that SpaceX has a profile on the massive social media platform and asked whether he would put his money where his mouth was, Musk responded: “I didn’t realize there was one. Will do.”

Musk also said that he had “literally never seen it even once”, presumably breaking the heart of the social media staffer whose job it was to create and manage the page in the first place.

Minutes later, both the Facebook pages of both Tesla and SpaceX had been deactivated.

A Tesla spokesperson declined to comment on the motivation.

Facebook has faced an onslaught of criticism from elected officials, former employees, the press and its own users in the wake of the Observer’s reporting that personal information about 50 million US Facebook users was harvested largely without users’ knowledge or consent and then improperly given to the political consultancy company Cambridge Analytica.

But Musk has long had a touchy relationship with Facebook’s chief executive, Mark Zuckerberg.

In 2016, Zuckerberg was a touch less than gracious about the accidental explosion of a SpaceX rocket carrying a satellite intended for use on his Internet.org project. “I’m deeply disappointed to hear that SpaceX’s launch failure destroyed our satellite,” he wrote at the time.

Musk also addressed that brouhaha, responding to a reporter’s tweet about the incident: “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.”

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. — Elon Musk (@elonmusk) March 23, 2018

The rival billionaires have also traded barbs over artificial intelligence. Musk has long pushed for regulation of AI, warning that the technology poses a “fundamental risk to the existence of civilization”.

In July 2017, Zuckerberg addressed Musk’s views in a Facebook Live broadcast, stating that focusing on “doomsday scenarios” was “really negative” and “pretty irresponsible”.

Musk shot back in a tweet, saying: “I’ve talked to Mark about this. His understanding of the subject is limited.”

Still, Musk’s commitment to deleting Facebook does not appear to extend to Instagram, the photo sharing service owned by Facebook where the billionaire frequently shares selfies and snapshots of his travels, cars, and rockets.

Asked about his continued use of Instagram, Musk tweeted: “It’s borderline. FB influence is slowing creeping in.”