Sen. John Fetterman (D-Pa.) compared tech mogul Elon Musk to Tony Stark, the alias for the fictional Marvel superhero Iron Man, highlighting that he appeals to a demographic that Democrats tend to struggle to identify with. During an appearance on "The Hill Sunday" with Chris Stirewalt, Fetterman said former President Trump is popular in Pennsylvania and noted that "it really does have me concerned more than the polls." While he said he expected the closeness in polls, he noted that Musk "is willing to actually show up at these kinds of rallies" with Trump. Musk joined Trump on the stage Oct. 5 at a rally in Butler, Pa., the site of the July assassination attempt on the former president. "Most endorsements don't count for much in this business, but Musk is ... incredibly popular, and he has an appeal to a demographic that Democrats have struggled with," Fetterman said. "To some people that they see him as, that's Tony, Stark," he added. "He's the world's richest man, and he's undeniably a brilliant guy." When asked by Stirewalt is Vice President Harris should counteract the Musk appearance, Fetterman said the Harris campaign has "plenty of surrogates and important kinds of endorsements." He noted that Democrats mock Musk, who is known to make jokes on stage and online. "If we ignore that as a problem... I think we could do that at our peril," he said. At the Butler event, the Tesla CEO slammed Democrats, saying they want to “take away your freedom of speech, they want to take away your right to bear arms, they want to take away your right to vote, effectively." Musk publicly endorsed Trump in July.