Elon Musk and Donald Trump hurled insults at each other all day on Thursday after the president’s former ally attacked the bill containing his entire legislative agenda. And though Musk had somewhat backed off his hardline stance a few hours later,

Musk attacked Trump directly over his signature spending bill for the first time Thursday, sparking an explosive back-and-forth.

President Donald Trump is mulling selling or giving away a red Tesla he bought in March. Trump and Elon Musk fell out on Thursday after the Tesla CEO harshly criticized a major tax bill the president wants Congress to pass.