Mark Zuckerberg says Elon Musk “isn’t serious” about a cage fight and “it’s time to move on” from their proposed showdown, the details of which were never nailed down. “Elon won’t confirm a date, then says he needs surgery, and now asks to do a practice round in my backyard instead,” the Meta chief executive wrote on social platform Threads Sunday. “If Elon ever gets serious about a real date and official event, he knows how to reach me. Otherwise, time to move on. I’m going to focus on competing with people who take the sport seriously.” Zuckerberg, 39, had previously proposed August 26 for the fight, but said Musk, 52, hadn’t confirmed. Last week, Musk wrote that the possible showdown would be streamed on X, formerly known as Twitter, which he owns. Musk said he was “lifting weights throughout the day, preparing for the fight,” adding “all proceeds will go to charity for veterans.” Zuckerberg, a practitioner of Brazilian jiu-jitsu, won gold and silver in two featherweight white belt categories at a California martial arts tournament in May. In June, the two tech billionaires seemingly agreed to face each other in a cage fight. The stakes for the potential clash were raised last month when Meta launched Threads, seen as a direct competitor to Twitter. On July 10, a few days after launch, Zuckerberg said more than 100 million people had signed up for the platform, making it one of the fastest-growing apps in history. But weeks later, industry estimates showed that Threads was struggling to retain users and that engagement had fallen to new lows.