Eco-Horror

Eco-horror makes the natural world the antagonist, usually in response to something people did to it. It tracks environmental anxiety almost exactly, which makes it the most datable subgenre here.

The Birds

Hitchcock's 1963 film offers no explanation at any point, which was unusual then and is the reason it still works. There is no score, only electronically generated bird sound. Tippi Hedren was attacked with live birds for five days in the attic scene and required a week off afterwards.

The 1970s: it is our fault

After Rachel Carson's Silent Spring (1962) the cycle turned explicitly ecological. Frogs (1972), Phase IV (1974), Long Weekend (1978), Prophecy (1979). The mechanism is usually pesticide, pollution or nuclear testing, and the moral is usually delivered without subtlety.

Long Weekend is the best of them by a distance. An Australian couple with a failing marriage camp on a beach, treat the environment with casual contempt, and the film simply lets the consequences accumulate. Nothing supernatural occurs.

Phase IV is ants, directed by Saul Bass, and looks like nothing else because Bass was a title designer and shot the insect sequences as documentary.

The Korean one

Bong Joon-ho's The Host (2006) opens with a real incident: an American mortician at a Seoul base ordering formaldehyde poured down a drain into the Han river in 2000. The monster is a consequence, the government response is the actual subject, and the film is funny, which nothing else in this category manages.

Now

The current wave is about climate and is less interested in a creature. Annihilation has no villain at all, only a process.