Elon Musk has a new nickname for Transportation Secretary Sean Duffy: “Sean Dummy.”
The childish name-calling, a cornerstone of President Donald Trump’s political style, does not appear to have landed quite as firmly as “Crooked Hillary,” “Lyin’ Ted,” or “Little Marco” has for the president.
The dig was part of the latest rift between Duffy and Musk, who is peeved that the Trump administration, which sidelined him in the spring, may pull federal contracts from SpaceX if another company can establish a moon base faster.
Musk, 54, posted to his X platform on Tuesday, “Sean Dummy is trying to kill NASA!”
The world’s richest man also replied to a flurry of posts about Duffy to “correct” the spelling of his name, writing, “*Sean Dummy.”
Musk’s outrage with Duffy, who is the acting administrator of NASA, stems in part from a CNBC segment on Monday in which Duffy encouraged private companies—like Jeff Bezos-owned Blue Origin—to overtake SpaceX as the leader in returning America to the moon if they can.
“I love SpaceX. It’s an amazing company. The problem is, they’re behind,” Duffy told CNBC. “They push their timelines out, and we’re in a race against China.”
Duffy, 54, said he and Trump want America to return to the moon and establish a base there by the end of the current presidential term, which is 1,186 days away.
“I want to get to the moon in this president’s term, so I’m going to open up the contract,” Duffy said. “I’m going to let other—other space companies compete with SpaceX, like Blue Origin.”
He continued, “Whatever one can get us there first, to the moon, we’re going to take it, and if SpaceX is behind, but Blue Origin can do it before them, good on Blue Origin.”
Duffy appeared intent on making sure Musk saw his interview, posting a clip on X.
“We are in a race against China so we need the best companies to operate at a speed that gets us to the Moon FIRST,” Duffy wrote. “SpaceX has the contract to build the [Human Landing System], which will get U.S. astronauts there on Artemis III. But, competition and innovation are the keys to our dominance in space, so @NASA is opening up HLS production to Blue Origin and other great American companies.”
Musk replied to the post on X, stating that he has “one question.” He then attached a meme GIF of an African TV host asking, “Why are you gay?”
The billionaire’s following replies were a bit more coherent. He also wrote, “Blue Origin has never delivered a payload to orbit, let alone the Moon.” He then added, “(useful payload).”
Musk has expressed displeasure at the possibility of NASA being folded into the Department of Transportation. He has also reportedly lobbied against Duffy becoming the permanent administrator of NASA. He is a close ally of Jared Isaacman, the billionaire founder of Shift4 Payments, who has been vying for the job for months.
Musk and Duffy also butted heads earlier in MAGA 2.0, when the Trump appointee pushed back against the Department of Government Efficiency’s attempt to fire air traffic controllers.
The billionaire has not tried to hide his disdain for Duffy, a former GOP lawmaker who graduated from the Mitchell Hamline School of Law in St. Paul, Minnesota.
Quote-tweeting a post that criticized Duffy’s leadership of NASA, Musk wrote on Tuesday: “The person responsible for America’s space program can’t have a 2-digit IQ.”
