It’s shortly before midnight when we arrive at Manaus’ Sambódromo. The atmosphere outside the concrete stadium with facing grandstands, purpose-built for Carnaval, is a bit Saturday night-at-the-rodeo meets samba party. Fireworks explode, half the friends I’m with are already drunk and screaming nonsensically, and so too are many of the others streaming inside.

Entering the Dromo’s main level from beneath the grandstands it’s a sudden, panoramic blur of impressions: there at stage-centre, the MC/bandleader/singer bedecked in a psychedelic bugle boy uniform is belting out lyrics against a batucada beat; behind him a battalion of shuffling drummers hammering out said thundering beat; and behind them other instrumentalists (guitarists, keyboardists, horns) against a weird painted backdrop that could be dubbed Alice in Amazonian Wonderland; the crowd on the floor is involved, engaged in synchronized, choreographed dance steps; those not dancing are chugging back beers and chatting with friends; there is a white plume of pyrotechnic fire scratching out sparks from somewhere amidst the throng; blue flags blurring as they furl this way and that; and best of all, on the catwalks flanking the stage, and on a float stationed in the middle of the stadium, handsome, lithe, and copper-skinned young women and men in kitschy but scant Indian costumes, gyrating along to it all.

And this is only a rehearsal. The big show, the Boi Bumbá festival, is yet two months away. When that happens, gigantic animatronic puppets will also be in the mix, plus more people and much more firepower. Still, there was no skimping on spectacle. Tickets are sold (10 Reais a pop), the beer vendors and food kiosks make brisk trade, couples make out, and the party keeps on keeping on deep into the night. Meanwhile the band works out this year’s batch of new songs, and its supporters (the galeras, who will be in attendance at the final showdown) learn the dance steps.

Boi Bumbá, also known as Bumbá Meu Boi, is the Amazonian version of Carnaval, with its own local folklore, sounds and iconography (although it must be noted Carnaval is also celebrated here, because, really: why have one massive blow-out party when you can have two). It culminates in a three-day contest during the last weekend in June, upriver in Paratíns, at which two competing teams—Caprichoso in blue, Garantido in red—struggle for Boi Bumbá supremacy as decided by the judges. Starting in March, the teams stage “practices” at the Sambódromo on alternating Saturdays. This is what the real thing looks like:

Each side’s performance is a re-enactment, an epic-scaled pantomime of a folkloric tale, in which the slave Pa Francisco slaughters his master’s bull to satisfy his pregnant wife’s craving for ox tongue. Learning this, the master uses some Indians to apprehend Francisco. But in true, syncretic Brazilian fashion, a priest and witch doctor together intercede to revive the bull, and Pa Francisco is saved. Through Boi Bumbá, this story is transformed into a densely allegorical, insanely choreographed, hedonistic, technologic party-ritual, led by bandleaders who pull it all together like twenty-first century shamans.

Of course, the celebration has little to do with “authentic” Indian or slave traditions, it’s more like one ritualistic riff, or mash-up based on whatever ideas are floating around in the cultural ether. The festival originated about a hundred years ago in Parintíns, a city of 100,000 located halfway between Manaus and Santarém on the Amazon River. By the 1990s it was transformed into a party to rival Carnaval; Manauans are lucky to play host to the rehearsals.

Boi Bumbá devotees demonstrate an enthusiasm for their chosen side shared only by futból supporters, albeit without the occasional propensity for violence. But as there’s no philosophical or geographical affiliation upon which to choose one’s “team”—really, there are no markers of difference other than colour—it’s an option based almost entirely on whim, unless you happen to especially like one side’s bandleaders. I ask my friend Omar, a native Manauana and culture editor at a local newspaper, why he supports Caprichoso (blue). “My family always supported Caprichoso while I was growing up. Then two years ago my sister decided she was for the red. Then, because of her, my mother changed to red. Now my whole family supports Garantido, and I’m the only one who goes for blue.”

Omar also points out that Boi Bumbá events are the places in the world where Coca-Cola permits its logo to appear in blue.

I was out on the Rio Negro much of the day, visiting ribeirinho (river people) communities along with field workers from a local ecological foundation, and was out late already the night before. The whole Boi Bumbá scene is enervating enough on its own and I struggle to take it all in. There is no shortage of drama, on stage or in the crowd. For a while I am fixed on a dancing, dwarfish, perhaps transgendered, indigenous man in too-tight spandex shorts, who is the closest thing I’ve ever seen to a real-life Shakespearean sprite. Then there’s the bandleader’s announcement during a rare stoppage, as the beat hardly ever ceases: “One of the drummers has just given birth backstage!”

And, like I said, this is only rehearsal.