Clinton said she wanted to put more money into the Social Security Trust fund and would raise taxes for the wealthy, which would include her, to pay for it.
She took the chance to take a swipe at her opponent, by saying that the tax rise would affect him too, "assuming he can't figure out how to get out of it." This was a dig at Trump's comments in a previous debate that he has avoided paying taxes, a move which he said was "smart".
This prompted the Republican candidate to interrupt to say: "such a nasty woman".
Of course Clinton fans went on the fight back immediately, with #NastyWoman trending on Twitter as a call to arms for women to join together against Trump. Someone clever even purchased the URL NastyWomenGetShitDone.com to redirect back to Hillary's website. Another is selling Nasty Woman tshirts, 50 per cent of the money made will go directly to Planned Parenthood in the US. Nice job.
Are you a bad hombre or a nasty woman? #Debate— Chelsea Handler (@chelseahandler) October 20, 2016
I hear the bathrooms in Trump Tower are being relabeled "Bad Hombres" and "Nasty Women."— George Takei (@GeorgeTakei) October 20, 2016
Brands are hopping on board too, with Teen Vogue putting this on Instagram:
A photo posted by Teen Vogue (@teenvogue) on Oct 19, 2016 at 8:49pm PDT
Some in the UK have said that the remark is comparable to when former cabinet minister Ken Clarke called prime minister Theresa May a "bloody difficult woman" earlier this year.
It's great to be a girl. You now have a choice: you can grow up to be a bloody difficult woman or a nasty woman— Ann Mroz (@AnnMroz) October 20, 2016
You can now get that on a t-shirt too, if that's what you're into.