Elon Musk - who is 'Twitter's main character'?
He's rich, owns Twitter and wants to get to Mars. Now he's feuding with Apple about advertising. If you're not up to date with Elon Musk's colourful history, here's what you need to know.
He's the richest person in the world
Elon Musk's fortune is guessed to be worth about $200 billion - a little more than Amazon founder Jeff Bezos. But that doesn't mean all that money is sitting in his bank account - the amount is worked out based on things he owns and what his companies are worth.
He made his first fortune with Paypal
Musk dropped out of the elite Stanford University in the USA to help launch two tech firms - one was Paypal, used to pay money on the internet. It was sold to auction giant eBay in 2002 for $1.5 billion.
He then turned to electric cars and space rockets
He put his money into Tesla, becoming chief executive of the electric car maker in 2008, and rocket company SpaceX. Both companies have had bumpy rides along the way, but Musk is often credited with making them a success.
He boasts about being a workaholic
People who know Musk say he only invests in things that he believes can help the human race, and he's called Twitter an important place to share ideas. So he's told staff to to expect "extremely hardcore" working to achieve greatness. Thousands have been sacked - or quit - since he took over.
He paid $44 billion for Twitter... even if he might not have wanted to
Musk joined Twitter's management in March 2022 but disagreed a lot with its top bosses - so decided to buy the whole company. It was messy - Twitter rejected his offer, then accepted it, then Musk tried to pull out. In the end, the sale was sorted out just days before a big court battle.
He's been quick to make changes
He said he bought Twitter to protect free speech - so he's already restored the accounts of controversial banned users such as Donald Trump. That's triggered a potential clash with Apple, which likes apps on its phones to be well-controlled. Musk says Apple has "mostly stopped advertising" on Twitter since he took over, asking if they "hate free speech".
He's been in trouble for his tweets
Musk has more than 119 million Twitter followers. In fact, he previously agreed to pay $20 million in fines over tweets about having "funding secured" to buy Tesla, which raised the stock price - but that never happened and the American business regulator wasn't happy. Part of the settlement involved putting limits on what Musk can tweet about Tesla.
He has many children
He has reportedly had a string of high-profile relationships including with actresses Tallulah Riley and Amber Heard, and musician Grimes. He and Grimes named one of their children 'X Æ A-12' - X for short.