The anarchists who plan to go nuts at the World Cup

However, speaking to GlobalPost, a veteran of Brazil’s radical protest movement said the Black Bloc is not an organization at all. Rather, it’s a tactic of demonstrators who are leaderless, angry and determined to raise hell.

“It is the 10 percent of the demonstration that don’t run from police, who are not scared. Nobody owns it,” said the protester, who identified himself only as AM because of the risks of arrest.

The tactic, AM explained, consists of militant protesters, often masked and wearing dark colors, swelling together in a block during demonstrations. They break into runs, jump and shout, helping to provoke confrontation. And when police inevitably react, they are not scared to hit back.

“It is the violence that has always been in the slums of Brazil but now has come to the center of town,” said AM, a 32-year-old native of Sao Paulo.