Republican presidential nominee Donald Trump and Democratic presidential nominee Hillary Clinton clashed on many issues during Monday's CNN debate: from economic policy and trade agreements to whether it is wise to disclose one's plan to fight ISIS (Trump has claimed that his is a secret.)

AP/Patrick Semansky - apimages.com

Though Trump maintained an air of aggression throughout much of the debate — lashing out at Clinton and the moderator, Lester Holt, quite a few times on stage, two of his most shocking remarks were not even in response to questions or follow-ups from Holt. Instead, they seemed to come out of left field.

One of these moments came amid an attack on Trump's business record and bankruptcies.

Clinton asserted that Trump "stiffed" hundreds of contractors, referencing a June USA Today story on a large group of former Trump employees who alleged that they were never paid for their work. In the report, USA Today claimed to have analyzed over 3,500 lawsuits, many of which include "carpenters, dishwashers, painters, [and] even [Trump's own lawyers – who say he didn’t pay them for their work."

Rather than deny Clinton's claim, Trump said, “maybe they didn't do a good job," essentially admitting to the allegations Clinton referenced.

Clinton also referenced her father — who sold drapes and window shades, the Washington Post notes — in an attempt to portray Trump as hostile to working people. "I’m certainly relieved that my late father never did business with you," she said.

Clinton also said that Trump had paid no federal income tax over the course of several years.

"That makes me smart," Trump replied smugly.

AP/Ricky Bassman - apimages.com

An August New York Times piece suggested that Trump hadn't released his tax returns because he didn't pay income tax, but those claims are based on pure conjecture.

From the Times:

"One obvious potential reason is that he reports little or no taxable income, and thus pays very little to support the government he wants to run. He is not obligated by law to make his returns public, but every candidate since Richard Nixon refused to has done so. (Gerald Ford released summaries.) Mr. Romney was harshly criticized for releasing just two years’ worth, and it became a major campaign issue four years ago.

"Even though his recent returns are confidential, the notion that Mr. Trump has paid little or no tax is not entirely speculative. It’s consistent with Mr. Trump’s returns from the late 1970s, which he filed with the New Jersey Casino Control Commission when applying for a casino license in 1981. Mr. Trump reported losses and paid no federal income tax in 1978 and 1979 and paid only modest sums — a total of less than $75,000 — for the prior three years."

The remarks — both of which seemed to pop up a bit out of the blue, rather than prompted by Holt — essentially walked straight into Clinton's argument that Trump is out for himself and his own business interests, rather than those of middle class voters and working Americans.