Name: Beware Boiúna
Director: Mike P. Nelson
Genre: Horror, Thriller
Released: 2026-09-17T00:00:00+00:00
Duration: 104 min
Cast: Kiana Madeira, Jessica Rothe, Logan Marshall-Green, Jackson Bews, Juan Pablo Shuk

The still Lionsgate chose to sell Beware Boiúna has no snake in it. Kiana Madeira and Jessica Rothe stand side by side in the wheelhouse of a river boat, framed by its rounded windows; behind them the water is flat and milk-grey, the far bank a thin green line, and a bronze bust sits in the corner of the frame like a passenger nobody invited. Mike P. Nelson’s giant-snake horror, now in North American theaters, sends a medical mission deep into the Amazon, where Boiúna, a colossal serpent out of Brazilian river folklore, wakes to take back her territory.

That empty water is the right place to start, because the legend is mostly water. In Tupi, mboi-una means black snake, and along the rivers of the Brazilian Amazon the Boiúna, also called the Cobra Grande, is the nocturnal ruler of the channels, a creature said to take the shape of a canoe, a sailboat or a woman to draw in the fishermen who stray into her reach. She is less a monster than a landlord. The film’s own synopsis keeps that hierarchy intact: in this jungle nature holds absolute power, and she decides who lives and who dies. The question the premise raises, before any monster enters the picture, is whether a German-American genre production can treat that landscape as an argument rather than a backdrop.

The casting points to a survival film that wants its people to matter before they are eaten. Madeira, who anchored Netflix‘s Fear Street trilogy, plays Lena; Rothe, the time-looping lead of Happy Death Day, plays Alli. Both arrive carrying the memory of horror heroines who outthink the genre around them. Logan Marshall-Green, the coiled lead of Upgrade and The Invitation, plays Brennan Malloy, and according to John Dotson’s review at The Cosmic Circus it is Brennan who gives the film its thesis in a sentence: no one belongs to the jungle. Lionsgate’s marketing promises “terror on a gigantic scale.” The cast suggests something closer to the ground.

Nelson builds his horror out of familiar shapes. He came up as a foley artist and sound designer before directing The Domestics, a post-apocalyptic road thriller, and then the 2021 Wrong Turn, a reboot written by Alan B. McElroy, the screenwriter of the original, which traded the old backwoods-cannibal clichés for a hidden mountain commune with its own law. His Silent Night, Deadly Night remake premiered at Fantastic Fest in Austin last year, and this September Beware Boiúna opened the same festival. McElroy is back as screenwriter, working from a story he developed with Tony Giglio. The pattern holds: take a horror template the audience thinks it knows and make it grimmer, and more territorial.

The subgenre had been sliding toward the joke. Anaconda became a camp touchstone, and Sony’s reboot last Christmas turned it into an outright meta-comedy with Jack Black and Paul Rudd. Nelson plays it straight. The production spent six weeks shooting in the Colombian Amazon, with Nick Junkersfeld as director of photography, and the warmest reviews read the result as a landscape film with teeth. At Dread Central, Matt Konopka called it “the scariest giant snake movie yet,” credited Nelson with holding the creature back in the manner of Jaws, and read Boiúna as the guardian of her rainforest against the miners and foreigners who come to strip it.

That restraint is also the film’s most contested choice. Daily Dead’s Matt Donato saw confusion where Konopka saw suspense: “Nelson has no sense of blocking; whatever intrigue happens on screen gets lost in a flurry of editing cuts meant to cover the snake’s most vicious material.” Rendy Reviews titled its verdict “Dude, Where’s My Snake?” The aggregates split the difference, with 56 percent positive on Rotten Tomatoes across 34 reviews and a Metacritic score of 49 at the time of writing. The release history does not inspire much confidence either: the film was announced as Titan, renamed Boiúna: Legend of the Amazon, and renamed again before it reached cinemas. And one question the reviews have not settled. Boiúna belongs to the Indigenous and riverside communities of the Brazilian Amazon, yet she arrives here through a German-American production, an English-speaking lead cast and a Colombian shoot. None of the coverage so far says whether the people who tell her story have any voice in the film beyond the creature itself.

Around the three leads, the credited cast includes Jackson Bews, Juan Pablo Shuk, Will Close, Vicente Peña, Jaime Newball and Nelson Camayo. Jeremy Bolt and Robert Kulzer produced for Constantin Film and JB Pictures in a German, American and Colombian co-production, with dialogue in English and Portuguese. The film runs 104 minutes and is rated R for bloody violent content, grisly images and language.

A still from the Amazon creature horror film Beware Boiúna (2026) — A still from *Beware Boiúna* (2026), directed by Mike P. Nelson

Beware Boiúna premiered at Fantastic Fest on September 17, 2026, and opened in US theaters through Lionsgate on October 2. Constantin Film releases it in Germany on November 12; in Spain it plays the Sitges festival on October 8 before opening in cinemas on October 16, and Italy follows on November 26.

Brazil, where the Boiúna is not a monster but a neighbour, comes almost last. The film opens there on December 3, two months after American audiences met her.