Long Weekend

An Australian couple with a failing marriage drive to a remote beach and treat it with total contempt. Nothing supernatural happens.

They throw rubbish out of the car. He shoots at things for entertainment, sprays an insecticide can at ants, chops a tree with an axe for no reason, runs over a kangaroo and does not stop. She burns things. Neither of them is likeable and the film has no interest in making them so.

Then the environment simply begins to respond, and the film never shows you a monster, never explains a mechanism, and never gives them a scene of realisation.

The dugong is the image people remember, and it is on screen for a long time doing nothing.

Colin Eggleston made it from an Everett De Roche script and it is the best eco-horror film ever made, largely because it declines every opportunity to become a creature feature.