Donald Trump has repeatedly described Joe Biden as mentally "shot" at his second campaign rally since his recovery from coronavirus.
Speaking to a packed crowd of thousands in the battleground state of Pennsylvania on Tuesday night local time, the US President mocked his Democratic rival for forgetting the name of Republican Senator and former Presidential candidate Mitt Romney.
"He's shot, I hate to tell you folks, he's shot," Trump told the audience at the John Murtha Johnstown-Cambria County Airport in Johnstown.
It came after the Republican accused the 77-year-old of having "dementia" in an early-morning tweet storm – a word Trump had previously avoided using in describing his opponent.
"You know Biden can't stand up to the lunatics in his own party," he told the audience.
"He can't even find his way off the stage without them. I'm running against the single worst candidate in the history of politics. That puts more pressure on me. Can you imagine if I lose to a guy like this?"
After the rally, he tweeted a photoshopped image depicting Biden sitting in a wheelchair at a nursing home with the words "Biden for Resident".
"Kinda makes me cringe. I wish he didn't go that far," one user said.
Another woman said, "Suburban women think making fun of the elderly is mean."
One added, "So he's making fun of being elderly. This should go over well."
Trump, who was a little less bombastic than during his appearance in Florida on Monday, repeatedly rambled back-and-forth from various topics as he riffed off the largely unchanged teleprompter speech.
He pointed to a recent Gallup poll that found 56 per cent of Americans felt they were better off today than four years ago – a question famously first asked by Ronald Reagan in 1980.
Asked about the poll on Monday, Biden said if people believed that "they probably shouldn't" vote for him.
"Their memory is not very good, quite frankly," the former Vice President told Cincinnati's WKRC.
Trump said 56 per cent saying "they're better off today than under Sleepy Joe and Obama" was "the highest of any President at this point in his term".
"Yesterday Biden told those 56 per cent of Americans that they probably shouldn't vote for him, and for once I agree," he said. "He has no idea what he's saying."
At one point he suggested that Democrat House Speaker Nancy Pelosi's attempt to set up a body under the 25th Amendment – which allows for the President to be removed from office if he is incapacitated – was not aimed at him.
"She's doing it for Biden, you know that," he said.
He added that it was "amazing, by the way" that "you only see it on the internet", referring to clips of Biden's gaffes.
"They never report it," he said, pointing at the assembled media. "They should report it. They're doing this country a great disservice by not reporting it."
Trump also boasted about his recovery from COVID-19, again claiming he was "immune" and joking that he could kiss the audience members.
"I could have stayed in the basement of the White House but I'm the President of the United States, I can't do that, I've got to get out and I have to meet people – I know it's risky," he said.
"Now I'm immune, they tell me, I'm immune. I could come down and start kissing everybody. I'll kiss every guy – man and woman. Look at that guy, how handsome he is. I'll kiss him, not with a lot of enjoyment, but that's okay."
Trump claimed that "they hate to say it because I had it".
"They used to say you're immune for life but once I got it they give you four months," he said, apparently referring to a new study by Harvard Medical School.
In comments that will likely be seized on by Democrats – healthcare has emerged as a key election issue – Mr Trump also bragged about the level of treatment he received.
"All I know is I took something, whatever the hell it was, I felt good very quickly – I felt like Superman," he said.
"One good thing about being President, if you're not feeling 100 per cent you have more doctors than you ever thought existed. There was like 14 of them."
Trump also renewed his pitch to "suburban women", a key demographic he struggles to win over, by claiming Mr Biden would "destroy your suburbs".
He was referring to his rollback of an Obama-era regulation known as Affirmatively Furthering Fair Housing, which proponents argued reduced barriers to racial discrimination but critics said handed undue power to the federal government to dictate zoning and land-use.
"They talk about the suburban women, they say, 'I don't know if suburban women like you, they may not like the way you talk.' But I'm about law and order, having you safe," he said.
"I don't want to build low-income housing next to your house."
Trump said suburban women "should like me more than anybody here tonight".
"I ended the regulation that destroyed your neighbourhoods, that brought crime to your suburbs," he said.
"I ask you to do me a favour – suburban women, will you please like me? I saved your damn neighbourhood, okay?"