“We’re not affiliated with any one specific organization,” said one of the demonstrators who unfurled the sign, when asked about the fake Antifa activists claiming credit.

But the people who were actually behind the banner said the alleged antifascist group, whose accounts on Twitter and YouTube have been pegged as elaborate satire designed to get a rise out of people on all sides of the political spectrum, had no involvement.

After a giant black banner cascaded over the Green Monster this week during a game at Fenway Park, with a message calling racism “ As American As Baseball ,” a group that goes by “Boston Antifa” claimed responsibility for the act of civil disobedience.


The banner appeared on the Green Monster in the middle of the fourth inning of the Red Sox-Athletics game Wednesday evening. It was prominently displayed for about two minutes before security officials intervened.

Almost immediately, the “Boston Antifa” Twitter account announced its “victory at the Red Sox game” and issued a convincingly in-depth statement describing why the group allegedly organized the action.

A YouTube video followed, showing a man wearing a mask over his mouth, breathing heavily as if he had just run from police, rereading the statement and calling for Major League Baseball to be dissolved. It was picked up by various news outlets in Boston as legitimate.

Antifa — short for “Antifascist” — groups have emerged across the country in the wake of President Trump’s election, with the aim of fighting back against white supremacists and “alt-right” provocateurs. The groups believe simple protests are not always enough to combat the rise of fascism.

Multiple attempts to reach the people who run the Boston Antifa accounts were unsuccessful.

The group’s videos — there are more than a dozen — have racked up hundreds of thousands of views online, and sometimes border on the absurd.

One featured video on the Boston Antifa YouTube channel, which was posted four days before the banner incident, is about how certain styles of fidget spinners, the popular toys used to entertain those who can’t sit still, cause post-traumatic stress disorder for victims of hurricanes because of their shape. Boston Antifa urges viewers to throw away the gadgets.


A second video, titled “Call to Action for the Men of Antifa,” directs male members to “start dressing as women at home” to better understand their female comrades.

Fake “Antifa” accounts have apparently become a problem across the country and are being used as a means to poke the hornet’s nest during a time of national unrest.

In August, a New York magazine blog reported that the Boston Antifa accounts, specifically, are “clearly not” legitimate.

In April, controversial right-wing personality, Gavin McInnes interviewed a couple said to be behind the group, in a segment called “Fun with fake ‘Antifa’ pranksters! Guests: @AntifaBoston.”

“There has been a tsunami of fake Antifa Twitter accounts and even videos,” McInnes said. “We spoke to one such group, first as their alter-egos ‘Boston Antifa,’ and then as themselves.”

Steve Annear can be reached at steve.annear@globe.com. Follow him on Twitter @steveannear. Travis Andersen and Michael Levenson of the Globe Staff contributed to this report.