Mike P. Nelson takes an ancient Amazonian serpent, a medical expedition and a considerable amount of mud, then sets out to make the giant-snake film frightening again. I was hoping for a bit more.
Film: Beware Boiúna (2026) · Director: Mike P. Nelson · Screenplay: Alan McElroy (story by Tony Giglio and Alan McElroy) · Starring: Kiana Madeira, Jessica Rothe, Logan Marshall-Green · Music: Stephen Lukach · Runtime: 104 minutes · My rating: ★★½/5 · Spoilers: Yes
A Familiar Shape Beneath the Water
When I first saw the trailer for Beware Boiúna, I had a rather familiar feeling. A boat was heading into the Amazon, a group of people were making the kind of decisions that never end well in a creature feature, and something enormous was waiting below the waterline. My immediate suspicion was that this would be Anaconda all over again, only without the conspicuous star power and gloriously questionable choices that made the 1997 film such an entertaining mess. I went in expecting an oversized snake, some disposable characters and perhaps a few amusingly inventive ways of making the cast disappear.
The film is a little more ambitious than that first impression suggested, and I can see why director Mike P. Nelson wanted to approach the material differently. There is a genuine attempt to make the landscape feel oppressive, to connect the monster to Amazonian mythology and to use the familiar survival premise to talk about exploitation. Unfortunately, those intentions do not always translate into a more engaging film. There were stretches when I was properly involved, but there were also stretches when I could feel those 104 minutes passing. I finished it without much difficulty, although I cannot say I was particularly excited by what I had watched.
The Shadow of the Other Big Snake
The unavoidable comparison is Luis Llosa’s Anaconda, a film that managed to assemble Jennifer Lopez, Ice Cube, Eric Stoltz and Jon Voight on an Amazonian boat and then let an implausibly determined serpent dismantle the expedition. It was silly in places, but never particularly ashamed of it. Voight’s wildly committed performance alone gave the film a personality that years of more expensive visual effects could not manufacture. There was a rough-and-ready pleasure to the whole enterprise, the sort of thing that belonged equally well in a cinema and on a late-night VHS rental.
Nelson’s film does not want that tone. It is dirtier, louder, more physically punishing and considerably more solemn, with characters weighed down by guilt, anger and private ambitions long before the giant snake arrives. I do not object to a serious creature feature, and nobody needs to repeat the original’s excesses for my benefit. But when a film strips away much of the camp, it needs to replace that pleasure with convincing character work and sustained tension. Beware Boiúna does some of that quite well, and some of it only intermittently.
The Journey Downriver, and the Trouble Waiting Ahead
The story follows a humanitarian medical team travelling along the Amazon’s Curuçá River, visiting isolated communities aboard the riverboat Hermes. Doctors Alli, Miguel and Callum are accompanied by captain Raúl and his adopted daughter Lena, whose familiarity with the river comes with a personal stake in what is happening around it. Lena is searching for her brother Jorge, who has become involved in documenting environmental destruction and resisting the people profiting from it. Their work brings the medical group into contact with a survey operation connected to Brennan Malloy and his brother Shawn.
A violent confrontation involving Shawn and Alli sends the entire expedition into a different sort of danger. What begins as a human dispute over violence, responsibility and control becomes a flight into increasingly hostile country, with Brennan pursuing the group and the river’s legendary predator awakening around them. The screenplay is trying to establish more than a set of snake attacks, and the collision between humanitarian intentions, commercial pressure and local resistance gives the story a potentially interesting foundation. It also takes a fair amount of time to arrange all the pieces, and I found myself wishing the early tensions developed with a little more urgency.
Lena, Alli and the People Who Should Have Stayed on the Boat
Kiana Madeira is the strongest reason to stay invested in the characters. Lena initially seems like one member of a larger ensemble, but her connection to the river and her search for Jorge gradually turn her into the film’s centre of gravity. Madeira gives her an appealing mix of impatience, vulnerability and hard-earned practicality. Her survival skills do not make her invincible, and the exhaustion that accumulates across the film matters more than any conveniently heroic speech. She is one of the few characters who begins to feel like a person rather than a name on the next casualty list.
Jessica Rothe’s Alli looks, at first, like the more obvious lead. Rothe has always been good at balancing determination and panic, particularly in the Happy Death Day films, and her rapport with Madeira gives the opening passages some life. Their different relationships with the river and the people living around it offer the film a useful contrast, even if their decisions sometimes seem designed mainly to propel the next disaster. I found it frustrating that the film was willing to dispense with characters who might have made the final stretch more emotionally involving, although the absence of guaranteed survival does at least lend the horror a certain bite.
Brennan and the Other Predators
Logan Marshall-Green’s Brennan Malloy supplies the human threat, a man whose anger and sense of entitlement become particularly dangerous when events escape his control. Marshall-Green is a capable actor, as anyone who remembers Upgrade or The Invitation will know, but Brennan is not an especially subtle creation. Much of his behaviour is driven by grievance and retaliation, and I occasionally wanted the writing to give him something more complicated to do than loom over people who were already frightened enough.
The supporting players help make the expedition feel physically credible, even when the script gives them limited room to breathe. Juan Pablo Shuk lends Miguel an air of professional competence, Will Close’s Callum provides another vulnerable perspective, and Jaime Newball’s Raúl anchors Lena’s relationship with the boat and the river. Jackson Bews makes Shawn unpleasant enough to start the human conflict, while Jorge connects Lena’s private search with the wider struggle over the rainforest. Individually, the performances do what they need to do. As an ensemble, though, they lack the memorable friction and eccentricity that can turn a collection of potential victims into a group worth remembering.
Boiúna, the Great Snake, and a Much Older Story
The creature itself is where the film has an opportunity to move beyond the standard oversized-animal formula. Boiúna, often associated with the Cobra Grande or Great Snake traditions of the Brazilian Amazon, is not simply a snake made impossibly large. Accounts differ across communities, but stories of a vast serpent haunting rivers, swallowing boats and possessing powers beyond an ordinary animal have circulated for generations. The river becomes more than scenery in these traditions; it is a place of danger, knowledge and forces that human beings cannot always command. That mythology gives the film a richer starting point than its trailer might lead anyone to expect.
The production also takes inspiration from Titanoboa cerrejonensis, a prehistoric giant snake known from fossils discovered in Colombia. I rather like the meeting of geological history and folklore, even if a fossil discovery does not, of course, validate the mythology. The trouble is that the film is often content to use this material as an ominous backstory while the creature behaves like the usual insatiable movie predator. Its more mysterious capacities become crucial only towards the end. I wanted more attention to the people who live with these stories and to the idea that the river’s great serpent might not operate according to a simple hunger for human flesh.
The Look of a Jungle That Doesn’t Want Visitors
One of the picture’s real strengths is the landscape. Filmed in Colombia, the jungle feels oppressive, humid and difficult to read, with the river stretching beyond the frame and vegetation blocking almost every useful sightline. Cinematographer Nick Junkersfeld and production designer Angélica Perea help create a world that looks lived in and uncomfortable rather than assembled as a convenient backdrop. The characters are forever wet, dirty or struggling to see where their next step might land. That physical discomfort gives the film a texture that many cheaper creature features simply cannot reproduce.
Nelson wisely understands that withholding the monster can be more effective than displaying it. An enormous body passing through a restricted space, movement glimpsed beneath a floor, or vegetation shifting just beyond a character’s vision can convey scale far better than a clean, brightly lit digital reveal. Some of those moments work beautifully, but the film occasionally pushes concealment too far. During the busier attacks, frantic camera movement, darkness and debris make it difficult to appreciate the creature. I could see the intention to keep Boiúna frightening; I was less convinced by the decision to hide so much of the very thing I had come to watch.
Making the Monster Feel Heavy
Nelson’s practical approach to a largely digital creature is one of the more interesting parts of the production background. Rather than relying only on actors reacting to an empty space, the crew used physical references and movement aids, including equipment dragged through the jungle to suggest the passage of an enormous weight. The method makes sense because a giant snake should disturb its surroundings, not float through them like an animated object pasted into the frame. A monster of that scale should compress the vegetation, change the rhythm of the scene and make the ground itself appear unreliable.
The director had initially been reluctant to make a giant-snake film, according to the production material, and his eventual interest came from finding a human story and a credible environment for it. The project began with producer Jeremy Bolt’s fascination with the Titanoboa discovery, with Robert Kulzer and screenwriter Alan McElroy helping develop it into the survival thriller we have now. I admire the willingness to make this sort of genre film on an actual difficult location rather than pretending that a few damp studio plants could stand in for the Amazon. What I question is whether all that effort produced a sufficiently distinctive screen monster.
Mud, Blood and Some Genuinely Nasty Moments
The film earns its horror credentials through a handful of properly unpleasant sequences. The botfly treatment is a particularly good example of how a small biological detail can make an audience squirm more effectively than a giant digital mouth. There is something about the intimate, physical indignity of such a scene that makes it hard to look away. Elsewhere, the deserted settlement and the evidence of what has already happened there turn the danger from a vague legend into a tangible threat, giving the characters a reason to be frightened before they have fully understood what they are facing.
Once the snake begins attacking the group in earnest, the film becomes increasingly brutal, with the riverboat sequence proving particularly consequential. Raúl, Alli and other members of the expedition are not protected simply because they have occupied important positions in the story. I respect that willingness to upset the expected order of survival, although the deaths are not always as affecting as they might have been with more time spent developing the people involved. The violence is graphic and the danger credible, but shock and suspense are not interchangeable; after a while, the pattern of sudden attacks begins to feel more exhausting than surprising.
The Strange, Low Sound of Something Moving Underneath
Composer Stephen Lukach gives the film an unusually abrasive sonic identity. In an interview with Eye for Film, he described working with Berlin-based musician Miako Klein, whose contrabass recorder was processed through pedals to produce deep, breath-like growls. It is a clever piece of sound construction because it avoids handing the serpent a conventional orchestral theme. Instead, the music seems to emerge from the landscape itself, somewhere between an animal exhaling, a machine grinding and a river making a noise it has no business making.
Nelson and Lukach also drew on the atmosphere of William Friedkin’s Sorcerer, with music and sound effects deliberately pushing against each other. I can understand the attraction: the expedition should feel as though every mechanical and natural sound is conspiring against it. At times the approach works, particularly before the attacks when small sounds begin to take on alarming significance. At others, the soundtrack becomes so insistently loud and heavy that there is little space left for quiet to do its job. I found myself wishing for more contrast, because a film can be oppressive without making every sequence sound like the world is coming apart.
The Ending: Who Gets to Leave the Jungle?
Full ending spoilers follow. By the final stretch, Lena and Brennan have been reduced to an uneasy struggle for survival. The human conflict that once seemed to drive the story matters very little beside the colossal creature moving through their surroundings. The confrontation moves towards industrial equipment, where Lena tries to turn the machinery of human control against a force that has rendered such control meaningless. Brennan’s last-minute intervention complicates his role without absolving him, and Boiúna ultimately kills him, leaving Lena to face the creature without the comfort of another person taking charge.
Rather than deliver the familiar giant-monster ending in which a convenient explosion resolves everything, the film allows Boiúna to observe Lena and spare her. Lena’s subsequent reunion with Jorge, and her involvement in the continuing resistance to environmental exploitation, reframes the serpent as something closer to a guardian than a mindless predator. I preferred that choice to the predictable spectacle of killing the snake, but it raises uncomfortable questions that the film is not especially interested in answering. If Boiúna can judge who belongs, who deserves punishment and who may survive, the story begins to resemble a moral fable, and its final acceptance of violent territorial justice deserves more thought than it receives.
A Creature Feature With an Ecological Conscience
The environmental argument is not difficult to recognise. The medical party arrives ostensibly to help, the survey operation views the rainforest as land to be assessed and exploited, and Lena’s family is embedded in the consequences of those competing ideas. Boiúna disrupts the confident assumption that the river belongs to whichever human group has the strongest equipment, the most money or the most persuasive explanation for being there. It’s a worthwhile premise, and certainly more interesting than using ecological damage as a throwaway excuse for a mutated monster.
I am less comfortable with how neatly some of the film’s moral implications eventually arrange themselves. Nature is not obliged to distinguish between good people and bad people, and an ancient serpent ought to be stranger than a very large instrument of environmental retaliation. There is also the matter of an Amazonian tradition being repackaged through an international English-language genre production. That can be a productive exchange when the underlying culture has room to speak, but here the mythology still feels a little too much like a distinctive label placed on a familiar Hollywood structure. The most intriguing material is present; it just rarely becomes the story’s organising force.
What Happened to the Fun of Monster Movies?
Perhaps I am simply old enough to remember a period when films such as Alligator, Piranha, Lake Placid and Deep Rising understood that the monster was only part of the attraction. The rest came from the characters, the atmosphere and the film’s willingness to enjoy the sheer absurdity of its premise. They were not all great films, and some were spectacularly uneven, but they generally gave the audience something to remember besides the number of people eaten. A certain unruly personality was part of the bargain.
Beware Boiúna seems almost suspicious of that pleasure. I don’t need jokes in every scene or a cast of comedians making wisecracks while the body count rises, but I do need a bit of energy between attacks. The seriousness is understandable, especially when the story is concerned with environmental exploitation and cultural memory, yet the screenplay often treats grimness as though it were a substitute for dramatic depth. I found myself missing the eccentricity of the older films, along with their willingness to let the audience enjoy a ridiculous cinematic situation without continually insisting that it was terribly important.
The Snake Was Big. The Impression Wasn’t.
To be fair, there are enough decent ideas here to keep Beware Boiúna from being dismissed as just another anonymous creature feature. The Colombian locations have genuine presence, Kiana Madeira gives the film a credible emotional anchor, and the creature’s best appearances show restraint and a sense of physical scale. The ending also makes a more interesting decision than the usual last-minute explosion, even if it leaves the film with an environmental argument that could have been explored much further.
But the weak pacing, thinly developed supporting characters, murky action and rather solemn tone kept me at a distance. My first impression from the trailer was that I was about to see a modern Anaconda without the original’s star power, and I cannot pretend that the finished film completely changed my mind. I managed to stay with it all the way through, and there are certainly worse ways to spend an evening, but the result was an okay creature feature at best. The filmmakers went to considerable lengths to make the snake feel enormous; I just wish the film surrounding her had made a bigger impression.
Production Notes and Further Reading
For the film’s development, location work and original production photographs, see the Praesens-Film distributor press collection and the Bloody Disgusting interview with Mike P. Nelson. Composer Stephen Lukach’s discussion of the score and its unusual instruments appears in Eye for Film. These sources provide useful context for the production, although the reactions and rating above are my own.
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