REVIEW: ‘Beware Boiúna’ Is More Than A Giant Snake Movie

Filmmaker Mike P. Nelson has been a noted up-and-coming voice in horror throughout the 2020s, and his hiring as director of the eleventh film in the Saw franchise has put more eyes on him than ever. Although he likely didn’t intend it, the Silent Night, Deadly Night (2025) helmer’s latest, Beware Boiúna, is a promising audition for the gig. An intriguing hodgepodge of creature-feature horror and anti-colonialist thriller, Beware Boiúna’s somewhat inconsistent narrative choices are offset by a consistent, gritty tone and naturalistic, driving performances. 

Alli (Jessica Rothe) and two other doctors are on a humanitarian mission along the Curuçá River to deliver medical supplies to Colombian villages, aided by boat captain Raúl (Jaime Newball) and his adopted daughter Lena (Kiana Madeira), who herself is searching for her missing brother. When Alli clashes with a road-building crew led by Brennan Malloy (Logan Marshall-Green) that spirals into a fatality for one of his crew, Alli and company are forced to retreat into the jungle. Instead of a solution, they find themselves in the den of the massive mythological serpent Boiúna.

It takes a long time for Beware Boiúna to get to the actual giant snake. Funny enough, that’s one of its greatest aspects. Early on, Mike P. Nelson and screenwriter Alan B. McElroy (working off a story from himself and Tony Giglio) build intrigue through the interpersonal tension between Alli and Brennan’s crews. It’s overused, perhaps, to say the characters feel like three-dimensional people, yet that descriptor fits perfectly here, given considerable life by their portrayers. 

Beware Boiúna takes its time bringing in the snake, shining the spotlight instead on its human characters.

Jessica Rothe has been a genre powerhouse ever since the Happy Death Day movies, and her nuanced work here helps Beware Boiúna get its hooks in the audience. Kiana Madeira (the Fear Street trilogy) similarly plays her role subtly and then ramps up, really coming alive in much of the film’s big scenes with the titular Boiúna. Logan Marshall-Green plays a morally compromised individual without going into full over-the-top slimeball territory, an approach that the rest of the movies follows. 

Rather than going for camp as any other giant reptile, sea creature, or what-have-you films usually do, Beware Boiúna takes itself 100% seriously. This gamble works and makes the inciting incident – which still happens before the titular snake shows up – feel explosive. It’s when we actually get to the marquee character that things start to get shaky. 

Beware Boiúna takes a massive risk in 86’ing a major character. While this adds unpredictability, it also takes one of our most fascinating performers off the board, so it feels miscalculated. The narrative, in general, has an odd relationship with “subverting expectations,” where unlikely team-ups, side characters being promoted to protagonists, and unexpected deaths are deployed for the sake of surprise rather than being motivated by the narrative. Mike P. Nelson works hard to sell it, making it work despite the nagging feeling that it would be more satisfying if it unspooled naturally. 

This creature feature doesn’t aim for camp. Instead, it goes full serious mode.

Confusingly, Beware Boiúna sidelines the Indigenous people of the Amazon. Outside of Lena, the other local characters feel like afterthoughts compared with their white counterparts. Furthermore, the actual mythological significance of Boiúna is underplayed to the point where it might as well just be any other giant snake.

Conversely, the film feels oddly scared to really engage in colonialism in a meaningful way. Some sort of consultation for the film’s portrayal of the Amazon would’ve gone a long way in ensuring authenticity and sensitivity here. 

All that said, when Beware Boiúna brings in the reptile, it’s a hell of a time. The grimy, dim lens of cinematographer Nick Junkersfeld – said in the most complimentary of ways – sells the vicious, pseudo-supernatural creature. It’s as much a clumsy wreaker of havoc as it is a graceful(ly brutal) god of destruction. You never see Boiúna too much, so when it shows up it feels monumental.

Saving the titular creature for key moments makes the build-up even stronger. 

Two major set pieces that jump out involve a grapple truck and a mud pit. In the latter, Kiana Madeira really gets to show her stuff as a horror protagonist, selling the desperation while being equally matched by longtime genre veteran Logan Marshall-Green. 

Beware Boiúna is more than just a giant snake movie. Although it has notable clunkiness in its storytelling- especially in subverting expectations and engaging in Indigenous culture – it’s remarkably rich in tone, performance, and, yes, the giant snake set pieces.

Most importantly, Beware Boiúna trades in irreverence for gravitas, making a film that’s all the better for it. That’s all to say that if the new Saw is indeed made by Mike P. Nelson, there’s reason to believe the franchise is in good hands. 

Beware Boiúna is now in theaters.