WASHINGTON (AP) — President Donald Trump on Thursday threatened to cut Elon Musk’s government contracts as their fractured alliance rapidly escalated into a public feud with Trump suggesting he would use the U.S. government to hurt his fellow billionaire financially.

The spectacular blow-up between the president of the United States and the world’s richest man played out on their respective social media platforms after Trump first broached the topic in a White House meeting with Germany’s new leader.

The rancorous breakup happened less than a week after they appeared together at the White House and Trump thanked Musk for his brief but tumultuous time in the U.S. government.

Trump had largely remained silent as Musk stewed over the last few days on his social media platform X, condemning the president’s signature tax cuts and spending bill. But Trump clapped back Thursday in the Oval Office, lamented their frayed relationship and said he was “very disappointed in Musk.”

Musk responded on social media in real time. Trump ratcheted up the stakes when he turned to his own social media network, Truth Social, and threatened to use the U.S. government to hurt Musk’s bottom line with his internet company Starlink and rocket company SpaceX.

“The easiest way to save money in our Budget, Billions and Billions of Dollars, is to terminate Elon’s Governmental Subsidies and Contracts,” Trump wrote on his social media network. “I was always surprised that Biden didn’t do it!”

“This just gets better and better,” Musk quickly replied on X. “Go ahead, make my day.”

The deepening rift unfurled much like their relationship started — rapidly, intensely and very publicly.

It also quickly hit Musk financially, even before Trump’s threat.

After Trump started speaking about Musk, shares of his electric vehicle company Tesla fell 9%, their latest notable move since the election. The shares doubled in the weeks after Trump was elected, gave back those gains and more during Musk’s time at DOGE and then rallied after he vowed in April to focus much more on Tesla and his other companies.

Musk later offered up an especially stinging insult to a president sensitive about his standing among voters: “Without me, Trump would have lost the election,” Musk retorted. “Such ingratitude,” Musk said in a follow-up post.

Politicians and their donor patrons rarely see eye to eye. But the magnitude of Musk’s support for Trump, spending at least $250 million backing his campaign, and the scope of free reign the president gave him to slash and delve into the government with the Department of Government Efficiency is eclipsed only by the speed of their falling out.

Musk announced his support for Trump shortly after the then-candidate was nearly assassinated on stage at a Butler, Pennsylvania, rally last July. News of Musk’s political action committee in support of Trump’s election came days later.

Musk soon became a close adviser and frequent companion, memorably leaping in the air behind Trump on stage at a rally in October. Once Trump was elected, the tech billionaire stood behind him as he took the oath of office, flew with him on Air Force One for weekend stays at Trump’s Mar-a-Lago club in Palm Beach, Florida, slept in the White House’s Lincoln Bedroom at the president’s invitation and joined his Cabinet meetings wearing a MAGA hat (sometimes more than one).

“I’ll be honest, I think he missed the place,” Trump said Thursday. “He got out there, and all of a sudden he wasn’t in this beautiful Oval Office.”

Musk bid farewell to Trump last week in a subdued news conference in the Oval Office, where he sported a black eye that he said came from his young son but that seemed to be a metaphor for his messy time in government service.

Trump, who rarely misses an opportunity to zing his critics on appearance, brought it up Thursday.

“I said, ‘Do you want a little makeup? We’ll get you a little makeup.’ Which is interesting,” Trump said.

The Republican president’s comments came as Musk has stewed for days on social media about Trump’s “Big Beautiful Bill,” warning that it will increase the federal deficit. Musk has called the bill a “disgusting abomination.”

“He hasn’t said bad about me personally, but I’m sure that will be next,” Trump said Thursday in the Oval Office. “But I’m very disappointed in Elon. I’ve helped Elon a lot.”

Observers had long wondered if the friendship between the two brash billionaires known for lobbing insults online would flame out in spectacular fashion. It did, in less than a year.

“Look, Elon and I had a great relationship. I don’t know if we will anymore,” Trump said.

The president said some people who leave his administration “miss it so badly” and “actually become hostile.”

“It’s sort of Trump derangement syndrome, I guess they call it,” he said.

He brushed aside the billionaire’s efforts to get him elected last year, including a $1 million-a-day voter sweepstakes in Pennsylvania. The surge of cash Musk showed he was willing to spend seemed to set him up as a highly coveted ally for Republicans going forward, but his split with Trump, the party’s leader, raises questions about whether they or any others will see such a campaign windfall in the future.

Trump said Musk, the CEO and founder of Tesla, “only developed a problem” with the bill because it rolls back tax credits for electric vehicles.

“False,” Musk fired back on his social media platform as the president continued speaking. “This bill was never shown to me even once and was passed in the dead of night so fast that almost no one in Congress could even read it!”

In another post, he said Trump could keep the spending cuts but “ditch the MOUNTAIN of DISGUSTING PORK in the bill.”

The bill would unleash trillions of dollars in tax cuts and slash spending but also spike deficits by $2.4 trillion over a decade and leave some 10.9 million more people without health insurance, according to an analysis by the Congressional Budget Office, which for decades has served as the official scorekeeper of legislation in Congress.

Besides Musk being “disturbed” by the electric vehicle tax credits, Trump said another point of contention was Musk’s promotion of Jared Isaacman to run NASA.

Trump withdrew Isaacman’s nomination over the weekend, days after Musk left his government role.

“I didn’t think it was appropriate,” Trump said, calling Isaacman “totally a Democrat.”

Musk, reverting to his main form of political activity before he joined forces with Trump, continued slinging his responses on social media.

He shared some posts Trump made over a decade ago criticizing Republicans for their spending, musings made when he, too, was just a billionaire lobbing his thoughts on social media.

“Where is the man who wrote these words?” Musk wrote. “Was he replaced by a body double!?”