This study explores the plants and plant-human hybrids of horror cinema, which are often called killers or monsters, through the lens of Michael Marder's inspirational book Plant-Thinking: A Philosophy of Vegetal Life, on vegetal ontology and plant thinking. To that end, it discusses the ethical and aesthetic possibilities of encountering the vegetal in cinema through a series of plant horror films shot between 1960 and 1980. These films, regarded as B movies, may be considered as inclining toward the vegetal themselves, not just because these films are about plants, but because their production and distribution preferences are open to the environment. Regardless of their intentions, these films-through their formal preferences, which do not reduce plants to a mere aesthetic object or object of fear to be defeated-allow us to see what is monstrous not only in monster plants but also in plants themselves. And in doing so, they invite us to encounter the vegetal and be somewhat plant-like ourselves.