The mushroom is having a moment. Its magical qualities and deep connection with the Earth have been explored in numerous recent releases, including Louie Schwarzberg’s Fantastic Fungi. Also journeying into the curious kingdom of the fungus, this psychedelic eco-horror directed by Jaco Bouwer reimagines the mushroom as an environmental avenger that awes and petrifies all at once.

Deep in the belly of the lush Tsitsikamma national park in South Africa, forest ranger Gabi (Monique Rockman) gets seriously injured after stepping on a makeshift trap. Rescued by Barend (Carel Nel) and Stefan (Alex van Dyk), a father-and-son survivalist duo, Gabi soon finds out, to her horror, that they are not alone. Mushrooms of all colours, shapes and sizes are sprouting, not only on trees and inside darkened hollows but also on Gabi’s own body. The contagion is beautiful and macabre, turning the infected into zombie-like creatures covered in colourful spores, blindly roaming around in the dark.

This affliction feels almost biblical: a Judgment Day visited upon human beings by a scorned Mother Earth. Indeed, Barend, a former scientist, now writes militant manifestos and delivers long sermons about the damage done to the precious ecosystem. The hypnotic cinematography reflects this fervent spirituality; in one dream sequence, a naked Gabi sprawls over a mossy patch next to a sparkling pond, an image that recalls Lars von Trier’s Melancholia. While the script could have used a touch more work – little, for example, is made of Gabi’s background compared with her male counterparts – the innovative visual effects, which combine CGI and practical makeup, are truly mesmerising. Deaths in horror movies don’t need to be all gore to chill – and here, the terrifying act of dying can also feel like falling into goddess Gaia’s embrace.

• Gaia is released on 27 September on digital platforms.