Billionaire Elon Musk said Saturday he is forming a third political party, after a dramatic falling out with Donald Trump, indicating he will make good on threats he made if the president’s domestic policy bill became law.

President Donald Trump on Sunday called Elon Musk's plans to form a new political party "ridiculous," launching new barbs at the tech billionaire and saying the Musk ally he once named to lead NASA would have presented a conflict of interest given Musk's business interests in space.