PARATY, Brazil –  Mud madness has taken over at a Brazilian Carnival street party where a mineral-rich black slime is a substitute for more traditional costumes.

Thousands of revelers from throughout Brazil and beyond converged Saturday at a beach near the colonial city of Paraty for the “Bloco da Lama,” or “Mud Street Party.”

Wearing only bathing suits, the party-goers threw themselves into a deposit of viscous black slime, emerging covered in sludge to dance to a pounding soundtrack and down prodigious amounts of beer.

Born in 1986, the party is among the most original of the thousands of “blocos” held throughout Brazil over the five days of Carnival.