SAN FRANCISCO - For most Americans, the "Proud Boys" and the "Antifa" might not have been household names, but both gained visibility following the presidential debate, prompting some people to look online to learn about their agendas.
When asked by the debate moderator on Tuesday to condemn white supremacists, President Trump's response suddenly elevated a group called the Proud Boys to the national spotlight.
"Who'd you like me to condemn? Proud Boys? Stand back and stand by. But I'll tell you what. I'll tell you what. Somebody's got to do something about Antifa and the left. Because this is not a right-wing problem. This is a left-wing problem," Trump said.
Former Vice President Joe Biden countered: "Antifa is an ideology not a group."
Shortly after, the name Proud Boys shot to the top of Twitter trends with thousands of mentions on social media along with thousands more for Antifa. Many Americans, wondering about both references.
On social media, Proud Boy members quickly reacted to President Trump's call with posts "Standing by sir" and "Sir we're ready."
So who are they?
"The Proud Boys came into existence about four years ago so a relatively new group," said Seth Brysk, regional director of the Anti-Defamation League in San Francisco, which tracks extremist groups.
Brysk said the Proud Boys have been linked to clashes in Portland Oregon and the 2017 Unite the Right rally in Charlottesville.
"Certainly many of them are white supremacists and do hold white nationalist and racist beliefs. Much of their leadership and membership is characterized by misogyny, anti-Semitism, anti-immigrant sentiment, Islamophobia," he said.
Proud Boys members, often seen in black Fred Perry shirts with yellow trim, have appeared in Bay Area rallies, denouncing Antifa, which stands for anti-fascism. The FBI says it's a movement rather than a group, which gained prominence after Charlottesville.
"It's a loose collection of people on the extreme left who are seeking to engage with people on the extreme right," said Brysk.
Antifa protestors have been seen committing acts of violence and clashing with far-right groups and police nationwide. President Trump has called for Antifa to be labeled a terrorist group.
Brysk says it's the Proud Boys which the FBI flagged as a danger.
"This is a group that just last month the director of the FBI identified as a serious threat, a threat on the order of domestic terrorism to the nation...so it's just not possible the president wouldn't have known who this group was, what they represented," said Brysk.
Republican Senator Tim Scott of South Carolina said he thinks the president misspoke.
Senator Kamala Harris called it a dog-whistle through a bullhorn.