Here's what to know about the feud between Donald Trump and Elon Musk over the president's "Big Beautiful Bill."

When Elon Musk denounced Republicans’ hefty spending plan as a “disgusting abomination” earlier this week, he largely steered clear of President Donald Trump, who has thrown his support behind the One Big Beautiful Bill. That changed on Thursday afternoon when the world’s richest man went after the world’s most powerful man.