La pieuvre

An octopus slithers over objects on land - a doll, a skull - then oozes along the shore into the sea. It secretes its ink. The camera follows it along rocks into deeper water, watching closely as it breathes. Its eye is closed then open. Simple titles, in French and German, suggest what to watch. The octopus alternates the use of breathing tubes on either side. It changes color as cells on its skin contract or dilate. Extreme magnification helps us see these changes. Two struggle, one dies... (imdb)