He had also just changed his Twitter bio to "Chief Twit".
Unfortunately, Mr Musk’s takeover of Twitter is no weak joke. While his brilliance as an innovative entrepreneur should be acknowledged, his erratic and self-centred nature is unsuited to ownership of a significant social media platform.
If he does not get things right, Twitter - already under pressure as a "hellsite" - could go down that sink’s plug hole.
Twitter has had an outsized influence in setting political agendas.
It has been much used by politicians and journalists even if public use is small compared to Facebook, Instagram and the like.
Of course, former United States president Donald Trump was infamous for his tweets. After being banned, he has tried - with limited success - to establish his own platform, TruthSocial.
Mr Trump has welcomed Twitter’s sale because it would "no longer be run by Radical Left Lunatics and Maniacs that truly hate our country".
Already, over the past few days, Twitter has been beset by a flurry of vile tweets.
Mr Musk himself has tweeted a conspiracy theory about the attack on the husband of House Speaker Nancy Pelosi.
This is a long way from what Mr Musk described earlier this year when he outlined his vision for Twitter as a "digital town square where a wide range of beliefs can be debated in a healthy manner".
Mr Musk is from the school of anything is possible, of faking it until making it, of busting and building, of ignoring the rules.
His driving the Tesla company and flying Space X and his sending up of thousands of low-orbit Starlink satellites are, nevertheless, remarkable achievements. He showed an eye for helping Tonga with free Starlink internet after its tsunami, and for internet support for Ukraine.
He then displayed his ignorance and arrogance with unconstructive comments about the war there. He appears to harbour delusions as a master of the universe, even more so than the other titans of tech.
He was listed by Forbes in March as the world’s richest man.
He blusters and blunders while innovating and investing. He and his ilk are an astounding feature of 21st-century capitalism, the modern-day "robber barons", those 19th-century American industrialists and financiers who made fortunes by controlling huge industries.
Twitter is a vanity project, ostensibly his libertarian contribution of "free speech", his gift to humanity.
"The bird is free", he tweeted several days ago, to which European Commissioner Thierry Breton responded: "In Europe, the bird flies by our rules".
Mr Musk has since made comments at times conciliatory and, typically, often confusing.
He talked about open-source algorithms, a positive development it would appear. He has said, "Twitter cannot become a free-for-all hellscape". He has spoken about Twitter becoming "the everything app", of extending the character limit, of premium subscriptions, of nothing too much changing until a content moderation council "with widely diverse viewpoints" was established.
Meanwhile, he fired the top of Twitter’s pecking order. And, in the last day or two, he weighed in on culling staff numbers.
Twitter relies on advertising for revenue. General Motors has paused its spending as it assesses Twitter’s direction. Other advertisers will not want to be associated with too much inane, dangerous, false and offensive content. Users, too, will desert the nest.
The US right gleefully welcomed what they saw as this slap in the face for progressives. Mr Musk’s vigour on free speech - although there is no shortage of hypocrisy on this front - was welcomed. But they will cringe at his views on abortion, LGBTI+ matters and climate change.
Mr Musk has taken on monumental challenges before. Somehow, many have taken off, albeit with wreckage in their wake.
Twitter might be another matter. We shall see.
