Why did Elon Musk get cold feet on Twitter?

Elon Musk's offer to buy Twitter was initially met with resistance.

In fact, Twitter evoked a "poison pill" provision to stop Musk from forcibly buying the company.

Eventually the company accepted the offer - a deal that Musk greeted with a one word tweet. "Yesss!!!"

A few weeks later though, Mr Musk appeared to have developed buyer's remorse. Having done all the running, having got what he wanted, he now had some questions.

"Twitter deal temporarily on hold pending details supporting calculation that spam/fake accounts do indeed represent less than 5% of users" he tweeted..

Mr Musk was arguing that Twitter had no way of verifying how many of its 229m daily active users were actually human.

Twitter's CEO, Parag Agrawal, answered back with a 13-tweet thread - publicly stating that fewer than 5% of its accounts were bots.

Elon Musk responded with a turd emoji.

That was on 16 May, and it appears not much has changed since then.

In Musk's filing to the US Securities and Exchange Commission (SEC) on Friday he said he had "repeatedly" requested further information on spam accounts - data that was not forthcoming.

Yet sceptics argue that Musk's interest in bots is a distraction.

Twitter is well known for having a significant number of fake accounts.

In fact, Twitter announced on Thursday that it removes a million bot accounts every day.

Twitter would readily have admitted it had a relatively small but persistent bot problem before Musk put in an offer.

Instead it's posited that bot and spam accounts are being weaponised by Musk, as an exit ramp out of this deal.

When Musk first looked into buying Twitter the tech economy was in a very different place.

At the end of March Tesla stock, which is the driver of most of Musk's fortune, was worth well over $1,000 (£830) a share.

Musk was feeling bullish. But since April, Tesla has lost about a third of its value. Many other tech stocks have also done poorly.

Musk's deal - that valued Twitter at $44bn (£36bn) - started to seem a little steep.

Many Tesla shareholders also began to worry that Musk's time, already spread between his companies Neuralink, Space X, the Boring Company and Tesla, would be spread even thinner with the acquisition of Twitter. It's difficult to see how it wouldn't.

Musk had other problems too. He claimed he wanted to take over Twitter because it had lost its way. He wanted Twitter to champion "free speech".

And yet he struggled to define how he was going to effectively moderate the platform to that end.

"By 'free speech', I simply mean that which matches the law," he tweeted.

But critics argued that that definition was naive. For one it would encourage countries to pass laws that restricted free speech. It would also cause a moderation nightmare - with different tweets being assessed in real-time for whether they broke the law (or not) in hundreds of jurisdictions.

And then there was Twitter itself. Musk never ingratiated himself to the bulk of Twitter's employees. He said that Twitter clearly had a "left wing bias" and joked that its head office could be used as a homeless shelter. Many Twitter workers were worried that his swashbuckling approach could undo years of carefully-thought-out moderation policy.

And as for Mr Musk's plan for Twitter? Well he had an ambitious growth forecast. In fact, he claimed he wanted to grow Twitter's userbase from 200 million to over 900 million in 2028.

Yet there was no clear vision of how he was going to do that. It felt like numbers picked almost at random.

To Musk's critics, he had bought a company at a high price, a company whose employees mostly didn't like him, and a company that he had struggled to present a coherent vision for.

To his supporters, Musk was going to change Twitter for the better. Donald Trump would be invited back. Twitter's overzealous restrictions on free speech would be reined in. Its inherent left-wing bias would be addressed. Mr Musk may now never get the chance to enact that change.

But this deal isn't over.

Twitter has already claimed that Musk is legally committed to buying the company - at the price agreed.

Twitter board member Bret Taylor has said they will take the matter to court.

It raises the bizarre spectre that Elon Musk could, unwillingly, end up buying a $44 billion company - an extraordinary thing.

A lot is still on the line. One thing is pretty clear though, this story is about more than bots.

James Clayton is the BBC's North America technology reporter based in San Francisco. Follow him on Twitter @jamesclayton5.