Neither Elon Musk nor Donald Trump are known for holding back on social media when they have an opinion, however inflammatory.
Now the pair have clashed with each other in an exchange in which Mr Musk told the former US president to “sail into the sunset”.
The first salvo in the spat appears to have been some less than positive comments about the Tesla boss that Mr Trump made at a rally in Anchorage, Alaska on Saturday.
He claimed Mr Musk was not going to buy Twitter and had got himself into a mess.
“(Musk) said the other day, I’ve never voted for a Republican,” Mr Trump said.
“I said I didn’t know that; he told me he voted for me. He’s another bull***t artist, but he is not going to be buying it (Twitter).”
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The SpaceX chief responded on Twitter: “I don’t hate the man, but it’s time for Trump to hang up his hat and sail into the sunset.”
“Dems should also call off the attack – don’t make it so that Trump’s only way to survive is to regain the presidency,” he added without explanation.
On Monday, Mr Musk added that if Republican Ron DeSantis ran against Joe Biden in 2024, “then DeSantis will easily win” and that “Trump would be 82 at end of term, which is too old to be chief executive of anything, let alone the United States of America.”