WASHINGTON — 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.”