Timeline: How Trump and Musk's relationship has unfolded over the years — from feud to alliance, and back again

The alliance between President Trump and Elon Musk went up in flames Thursday, days after the world's richest man left the administration and tried to wield his influence to kill a massive budget bill that is central to enacting the president's top legislative priorities. 

Their spat played out in public and marked another remarkable turn for Musk, who spent tens of millions on Mr. Trump's reelection campaign and was given the reins to slash the size of the federal government. 

Here's a look back at how Mr. Trump and Musk got here: