Billionaire tech executive Elon Musk cast the upcoming presidential election in dire terms during a Saturday appearance with Donald Trump, calling the Republican presidential nominee the only candidate “to preserve democracy in America.”

The CEO of SpaceX and Tesla who also purchased X, Musk joined Trump in Butler, Pennsylvania, where the former president survived an assassination attempt in July. He warned “this will be the last election” if Trump doesn’t win and, clad in a black-on-black cap bearing the “Make America Great Again” slogan of Trump’s campaign, appeared to acknowledge the foreboding nature of his remarks.

“As you can see I am not just MAGA — I am Dark MAGA,” he said.

The appearance marked the first time Musk joined one of Trump’s trademark rallies and represented the growing alliance between the two men in the final stretch of a competitive presidential election. Musk created a super PAC supporting the Republican nominee that has been spending heavily on get-out-the-vote efforts in the final months of the campaign. Trump has said he would tap Musk to lead a government efficiency commission if he regains the White House.

Trump joined Musk in August for a rare public conversation on X, an overwhelmingly friendly chat that spanned more than two hours. In it, the former president largely focused on the July assassination attempt, illegal immigration and his plans to cut government regulations.

Before a massive crowd on Saturday, Musk sought to portray Trump as a champion of free speech, arguing that Democrats want “to take away your freedom of speech, they want to take away your right to bear arms, they want to take away your fight to vote, effectively.” Musk went on to criticize a California effort to ban voter ID requirements.

Saturday’s rally took place at the same property where a gunman’s bullets grazed Trump’s right ear and killed his supporter, Corey Comperatore. The shooting left multiple others injured.

Several members of Comperatore’s family, as well as other attendees and first responders from the July rally, returned to the site on Saturday. Also appearing with the former president were his running mate Republican Ohio Sen. JD Vance, son Eric Trump, daughter-in-law and RNC co-chair Lara Trump, along with Pennsylvania lawmakers and sheriffs.