Lara Pop’s review published on Letterboxd:
I often wonder: what is a real horror movie? Stories about zombies, vampires, demons, monsters etc. are all horror movies. But are they real? Do they inject real fear in me? I enjoy them but I never see reality reflected in them. The incision between film and real life remains a clearly defined wound but I never feel reality dissolve in it, become one with it. I simply watch the movie and enjoy the hell out of it.
Possession is different. It not only dissolves, but devours reality. It does so in a way that the wound of what's depicted on screen pulsates with the tainted blood of reality. It becomes reality. We see Anna keep a tentacled monster in her apartment but the creature is not what's there in reality, it is not the real horror. The real horror is what it represents in Anna's and thus our reality. We see Anna have a blood-chilling miscarriage in an abandoned subway while she flails around as if one who's possessed, but it is not the moist screams or the body horror that are truly disturbing but the visual manifestation of Anna's disturbed (far gone) state of mind.
Real horror lies not in blood and gore, not in what can be seen. Real horror lies in the implications of that which is seen. It lies in the implicit that comes alive in the audience through the explicit.
We harbor our real monsters inside. Its tentacles that crawl into the world are but the reflections of our inner reality. How they manifest in the tangible world is but an afterthought, a mere outward consequence. The monster in Possession has never been the true reality, never been the true horror, and the film understands it. This was one of the most blood-curdling cinematic experiences I've had. Zulawski for the win.