“I propose a literal d**k measuring contest,” Musk said amid the much-hyped, on-gain, off-gain, and-this-week-on-again mixed martial arts showdown.

The takeover of X, nee Twitter, turned a long-simmering rivalry between eccentric Silicon Valley figures into the direct corporate conflict between bitter industry competitors. Zuckerberg quickly launched Threads to siphon away the customer base Musk burned USD $44bn (A$67b) to own.

Musk sent legal threats and issued a challenge to duel at the Colosseum. Zuckerberg proposed August 26. The cage match will be live-streamed on X. No, on Threads.

Well that escalated quickly.

Their relationship first exploded into a feud alongside a USD$200m (A$306m) satellite that Zuckerberg had strapped to one of Musk’s SpaceX rockets. The Falcon 9 booster went boom, not in a good way, before getting off the launch pad in 2016.

While the next seven years of shade were full of public jabs and side eyes, their snarky tone oscillated around the “per my last email” level of office politics. Zuckerberg was “deeply disappointed” with SpaceX, and criticised the “naysayers” of artificial intelligence. Musk lamented that Zuckerberg’s “understanding of the subject is limited”.

By the time Threads was announced, the potshots reached a level of kayfabe that would make Hulk Hogan and Mucho Man blush. Musk sent a cease-and-desist letter alleging Zuckerberg hired ex-Twitter staffers for their proprietary information, a claim vehemently denied by Meta lawyers.

“I’m sure Earth can’t wait to be exclusively under Zuck’s thumb,” Musk said of the Twitter competitor, before challenging Zuck, the “cuck”, to a “cage match”.

“Send me location,” the Facebook founder hit back, echoing the famous catchphrase of Russian UFC fighter Khabib Nurmagomedov in his challenge to Irish MMA champion Conor McGregor.

In one corner is the richest man in the world with a net worth of USD $232.5bn (A$355b), in the other corner is the seventh at USD$110.1bn (A$168b). With the build of an iron lung, the grace of a sumo and hailing from the planet Mars, Musk weighs in “at least” 136 kgs, 6’2”, and proudly never trains. Zuck, who rumours suggest may or may not be part lizard, from parts unknown, clocks in at 70kg, 5’7”, and shamelessly poses with his Brazilian jiu-jitsu six pack.

It’s the member versus the contender. Who wins in the cage. Who wins in court. And who wins the hearts and scrolls of Twitter’s 353.90 million users will be less about their fame or fortune and more about the wildcard inside Musk.

The polarising South African allures and alienates people wherever he goes. Salty Twitter staff and users staged a performative exodus after his takeover. The left-wing city of San Francisco forced him to take down his new ‘X’ logo. A court fined the company USD$350,000 (A$535,000) for its delayed response to a US Department of Justice search warrant demanding the account data of former president Donald Trump.

Zuckerberg isn’t being held in contempt but he isn’t doing much better when it comes to Threads, either. Days after launch it reached 100 million users, but almost immediately lost engagement and by the end of July had lost more than half its users. Only 8 million remain active daily. Meta has promised to retool.

Both have enough money to burn on software engineers, fight trainers and corporate lawyers. The difference will be the devil inside. On that measure, at least, Musk wins.

“There are a lot of weird things and demons and drive that motivate him. Money isn’t number one,” says author Walter Isaacson, who spent three years shadowing the mogul for a biography releasing in September. “He has a demon mode that is destructive.”

Musk loves the destruction. The fight. The contentiousness of putting an impulsive tweet out into the ether and bathing in the glow or consequences, whatever they may be, that blow back.

“You know what his favourite line in a movie is? ‘Are you not entertained?’ That final line of Gladiator,” Isaacson added to CNBC. “And that’s what’s distinguishing Twitter, for better and for worse, against things like Threads … he finds [Threads] boring.”

If the two do lock horns in the ruins of the Colosseum, expect to be entertained. Dana White, president of the Ultimate Fighting Championship, said it will be “the biggest fight in the history of combat sports”.

He says Zuckerberg is singularly focused on training and fighting, while Musk has made “very clear” he’s not going to train, lose weight, or otherwise prepare.

“I’ve been talking to Zuckerberg now for maybe close to two years now and there’s never like banter or we’re joking and laughing,” he said, adding the Meta CEO was “dead serious all the time.”

Zuckerberg has a blue belt in mixed martial arts and a full-sized octagon cage in his backyard to practice. Musk suffered a neck injury during a novelty sumo wrestling match and says he needs an MRI, and maybe an operation to strengthen the titanium plate holding together his C5/C6 vertebrate, before the fight can go ahead.

“If I was Elon Musk, I’d be staying well away from it,” said boxing promoter Eddie Hearn. “If you go in a cage with someone that knows how to do Brazilian jiu-jitsu, like, it’s over.”

Whoever wins, the scrap promises to echo the chaos and spectacle of Twitter rather than the mild curiosity and vacuousness of Threads. Unless, of course, the contest devolves into mathematical calculations of length, girth and weight threatened by Musk. Blame his occasional paramour and co-parent Claire Boucher, aka Grimes, aka ‘c’ – or the speed of light in physics nomenclature, for that visual.

“I was like, why don’t you cut to the chase and get out a ruler. I didn’t think he was going to tweet it,” she of the fight, which she fully expects to happen.

“Elon is very strong, but Zuck seems like he’s been training a ton. I would prefer that it didn’t happen. I love gladiatorial matches, but watching the father of your children in a physical fight is not the most pleasant feeling,” she added to Wired. “But it’s not going to cause brain damage, so actually I think this is good. Dudes need some outlet for trad masculinity.

“I actually think it’s making them respect each other more.”

Isaacson, who this week revealed in an excerpt of his upcoming biography that Grimes was wooed by “f**king crazy” Musk blindfolding himself behind the wheel of a self-driving Tesla, said regardless of whether the fight actually goes ahead, the two are already in the throws of an all-out brawl.

“I think we’re watching the cage fight. I think it’s a metaphor, no pun intended, for the Meta fight with Twitter, but we’re not really gonna go to the Colosseum in Rome.”

Maybe no, or maybe so. If Musk is to be taken literally, which his self-professed Asperger’s personality on the spectrum suggests he is often being, the two gladiators just may duel it out in the arena. But it might also settle nothing other than who has the biggest swinging dick in Silicon Valley.