Hillary Clinton was giving a pretty normal policy response about Social Security at the third presidential debate on Wednesday. In the process, she got in a small jab at Trump.

“I am on record as saying that we need to put more money into the Social Security trust fund — that’s part of my commitment to raise taxes on the wealthy,” she said. “My Social Security payroll contribution will go up, as will Donald’s, assuming he can’t figure out how to get out of it.”

It was a reference to the reports that Trump once wrote off a loss so large that he may not have paid taxes for as much as 18 years. The suggestion being that if Trump got out of paying taxes before, he could dodge paying his Social Security taxes in the future, even if Clinton raises the payroll tax for the wealthy.

Trump did not appreciate it. “Such a nasty woman,” he said.

Once again, it bears emphasizing that this kind of behavior is not normal on the presidential debate stage. Normally, candidates may disagree, criticize, and get in some zingers, but direct insults like Trump’s are just weird.

Watch: This debate isn’t just Democrat vs. Republican. It’s normal vs. abnormal.