Elon Musk’s biographer, Walter Isaacson, said the SpaceX CEO is in “demon mode” over the prospect of NASA being folded into the U.S. Department of Transportation.
Isaacson, who spent two years shadowing Musk, 54, added some color to the Tesla CEO’s feud with Transportation Secretary Sean Duffy, in a Thursday interview with CNBC’s Squawk Box.
“He’s in ‘demon mode’ now over the question of whether NASA, the space agency, should be folded into the transportation department,” he said.
The former CNN head said Musk’s “one-time girlfriend Grimes,” with whom he shares three children, coined the term for Musk’s periods of rage.
Duffy, who is the acting administrator of NASA, has been pushing for the agency to be placed under his department’s purview since the summer, according to a Monday report from The Wall Street Journal.
Sean Dummy is trying to kill NASA! https://t.co/cP0RxP09rt
— Elon Musk (@elonmusk) October 21, 2025
The news prompted Musk to throw a childish jab at him on Tuesday, saying, “Sean Dummy is trying to kill NASA!”
Later that day, Musk again launched a similar insult at the transportation secretary.
“Sean ‘Dangerously Stupid’ Dummy. The part in quotes is his call sign Didn’t want to forget that,” he wrote.
Sean “Dangerously Stupid” Dummy. The part in quotes is his call sign. Didn’t want to forget that.
— Elon Musk (@elonmusk) October 21, 2025
Isaacson, who wrote the acclaimed biography of Apple founder Steve Jobs, explained that the feud began after President Donald Trump withdrew Musk’s preferred pick to helm the agency in May.
“Trump told Musk before it became public, ‘I’m yanking Jared Isaacman’s appointment,’ that caused Elon Musk to really go ballistic, so to speak. And it’s not because Jared Isaacman is some close personal friend,” he said. “Isaacman is a true test pilot. Somebody who’s flown in space vehicles.”
Isaacman, the 42-year-old billionaire founder of payment processor Shift4 Payments, has flown on two SpaceX flights.
Days after his nomination was pulled, Musk began publicly feuding with Trump, kicking off on June 5 when he said the president is in the so-called Epstein Files.
“Elon strongly believes he’s needed at NASA,” Isaacson said. “And Elon is not using the most diplomatic means to try to push that on the administration.”
Musk posted a flippant poll on Tuesday, questioning who should helm NASA.
“Should someone whose biggest claim to fame is climbing trees be running America’s space program?” he wrote on X.
Should someone whose biggest claim to fame is climbing trees be running America’s space program? 🤔
— Elon Musk (@elonmusk) October 21, 2025
The arboreal jab is likely a reference to Duffy winning a 1994 tree-climbing title at the Lumberjack World Championships in Wisconsin.
“Yezz, chimps skillz rūl!” was one option, with the other, winning choice being, “Noo, he need moar brainz!”
The feud reignited when Duffy said Monday that the Trump administration could pull SpaceX’s federal contracts if another company can produce moon landers faster.
“We’re in a race against China, the president and I want to get to the moon in this president’s term,” he told CNBC on Monday.
A NASA spokeswoman pointed to Duffy’s response to a tweet from Musk when the Daily Beast requested a comment.
“Love the passion. The race to the Moon is ON. Great companies shouldn’t be afraid of a challenge. When our innovators compete with each other, America wins!” Duffy wrote Tuesday on X.
Love the passion.The race to the Moon is ON.Great companies shouldn’t be afraid of a challenge.When our innovators compete with each other, America wins! https://t.co/P8gYX7R0mp pic.twitter.com/mAoGG1bq8c
— NASA Acting Administrator Sean Duffy (@SecDuffyNASA) October 21, 2025
Elon Musk did not immediately respond to a request for comment.
The post Why Elon Musk Is in ‘Demon Mode’ Right Now: Biographer appeared first on The Daily Beast.
