Parasite

Parasite horror confronts us with organisms that live inside or on us — feeding, reproducing, taking control. The parasite violates the most fundamental boundary of selfhood: the distinction between your body and something else's. Unlike a predator that attacks from outside, the parasite infiltrates, colonizes, and repurposes. Your body becomes its habitat, and you may not even know it's there until the damage is irreversible.

Cronenberg's Shivers (1975) is the subgenre's foundational text. The parasites in that film are not merely dangerous — they rewire their hosts' behavior, turning rational people into aggressive, sexually compulsive vectors for further infection. The horror is not just biological but philosophical: if something can alter your desires and impulses, are you still you? Alien (1979) gave parasite horror its most iconic image — the facehugger implanting an embryo, the chestburster erupting from within — transforming the human body from person to incubator.

The subgenre encompasses both the literal and the metaphorical. Slither (2006) played parasitic infection for horror-comedy. The Bay (2012) used found footage to depict a waterborne parasite devastating a small town. Assimilate (2019) and The Host (Bong Joon-ho, 2006, though more creature than parasite) expanded the form's international reach. What connects these films is the intimate violation they depict — not an attack from outside but a colonization from within, turning the body into territory occupied by something alien to your will.