When the environment itself and ancient species team up against people, people will rarely win. This is the problem facing a group of volunteer doctors in Beware Boiúna, boating down the Amazon River to provide medical care to isolated communities.
Led by a few locals familiar with the jungle, they travel from village to village, diagnosing malaria, treating wounds, and meeting the locals with kindness. They are warned that they are in Boiúna’s world, an enormous snake who protects the river and decides who lives and dies. Another boat shows up in their waters, causing tension, because they are a group of surveyors scoping out land for future development. When their conflict comes to a head after a violent accident, they are in a game of cat mouse with each other, and then suddenly, with Boiúna. The humans have to fight unfamiliar environmental conditions as they run from a snake that won’t stop hunting them.
The environment and the snake are the best aspects of Beware Boiúna. The Amazon river and the jungle communities are completely unfamiliar to most, if not all, of the film’s viewers. The insects, plants, and animals with myriad ways to kill people are everywhere you turn. Boiúna herself delivers exactly what a creature in a creature feature should: we see just enough of the snake to be afraid, but they don’t show so much that it ruins the mystery. Her ability to withstand attacks from the humans and swallow them whole makes her unstoppable.
The film’s weakness is its humans. The doctors are largely likeable, but when Jessica Rothe’s character makes a choice that leads to irreversible consequences, it’s hard to sympathize with her decision-making. The surveyors are supposed to be disliked, and it’s easy to hate them, but they also make some threats that feel out-of-step with the rest of the film’s tone. Kiana Madeira’s character is the most sympathetic, but when her decisions alter in the film stop making sense, it becomes harder to feel for her character.
The tone and theme caused whiplash because the film can’t decide if it’s for or against people impacting the environment. We are made to sympathize with Boiúna early in the film, which makes it hard to root for any of the humans to survive. By contrast, it’s easy to root for the humans in Jaws (1975) because the shark is set up as a monster from the beginning. But in Beware Boiúna, audiences are primed to root for the snake, which makes it harder to hope for the humans’ survival.
Overall, Beware Boiúna is a solid creature feature, with beautiful scenery and a scary big snake, that’s somewhat hindered by its tonal whiplash and uneven themes. Enjoy the squirmy body horror throughout, some medical and some caused by Boiúna herself, and the tension as you wait to see who she will kill or let live.
Beware Boiúna had its world premiere at Fantastic Fest 2026 on Thursday, September 17
