Democratic front-runner Joe Biden struggled to recall the word "escalator" while bashing President Trump during a campaign stop in Miami.

Speaking at the historic Ball & Chain nightclub on Sunday afternoon to mark the start of Hispanic Heritage Month, Biden slammed the president's June 2015 comments about Mexican immigrants made during his 2016 campaign announcement speech.

"Remember when he came down, uh, down the, uh — his golden escalator of Trump Tower," Biden said, "he announced on the way down, one of the reasons he was running was because of all those Mexican rapists."

Biden then brought up last month's mass shooting in El Paso, Texas, citing the shooter's alleged manifesto that indicated he was attempting to stop the "Hispanic invasion of Texas" by opening fire on a local Walmart and killing nearly two dozen people.

"That was right after the president talked about in the off-year election, 'The invasion is coming north, the invasion that is going to swamp America's values,'" he said. "Folks, that's not who we are."

Biden made the remarks as he was wooing Latino voters in Miami's Little Havana neighborhood. Democratic insiders are concerned Florida could remain in GOP hands in 2020 despite Hispanics representing the fastest growing voter bloc in the battleground state. His struggling to remember the word "escalator" comes amid intense scrutiny over his "mental fitness" after several verbal blunders on the campaign trail and poor debate performances.

The former vice president and Vermont Sen. Bernie Sanders currently lead the Democratic field among Hispanic voters nationwide.