Partakers in this unusual carnival party in Paraty drape grey sludge on themselves and roll around in the silty shallows of a beach, forming a unified mass.
"Everyone is kind of the same (…), those who have money and those who don't: everyone comes here to jump into the mud," said Charles Garcia Pessoa, a 37-year-old entrepreneur.
Under a blazing sun, the mud-covered partygoers danced and grunted cavemen chants — "Uga! Uga!" — while marching along the sand, accompanied by musicians.
The tradition started in 1986, according to Paraty's tourism site.
Friends were playing in the mangroves at Jabaquara Beach, and realised they weren't recognisable. They went strolling into the city's historic centre and caused a stir.
The next year, a group lathered themselves up with mud to present themselves as a prehistoric tribe for Carnival. They carried skulls, vines and bones as they uttered their chants, the site said.
And so the mud party was born. And in the years since, it has become a beloved tradition.
Matt Bloomfield, a New Zealander who runs a film festival, decided to come to Paraty for the mud party after seeing coverage of last year's event.
"Everyone's being so creative, you see people around decorating themselves with leaves," he said.
"It's a great alternate version of Carnival."
