In the middle of what's been a never-seen-before public fallout between arguably two of the most powerful men in the world, US President Donald Trump said that billionaire Elon Musk was suffering from "Trump derangement syndrome." On Thursday, the two trained guns on each other, with Trump saying he was "very disappointed in Elon" after his criticism of the "Big Beautiful Bill" on tax cuts and spending plans. Musk, among other things, suggested Trump should be impeached.