Trump publicly denounced Musk during a tense Oval Office press conference on Thursday, saying that he was “disappointed” and “surprised” that the tech billionaire opposed his “big beautiful bill.” He went on to suggest that Musk has “Trump Derangement Syndrome”—an insult Trump typically hurls at his opponents and critics.

Once allies, Trump and Musk are now engaged in a war of words. Trump claimed Musk knew the details of the tax bill but only opposed it after EV incentives were cut. Musk denied ever seeing the bill and blasted it as fiscally irresponsible.