yarb’s review published on Letterboxd:
Possessor takes the primal horror trope of mind-body dualism and dissects it with a cold-forged meat cleaver. For every scene of psychological terror, as identities bleed into each other and struggle to stay coherent, there's a bloody violation of corporeal boundaries to match. The core concepts here aren't new but Cronenberg's examination of them is bold and visceral.
Set in an uncanny 2008, Jennifer Jason Leigh reprises her role from Annihilation as an impassive psychologist shepherding travelers into — and hopefully back out of — an alternate reality. But here, the alternate reality is other people's bodies, and the task of star "possessor" Tasya Vos (Andrea Riseborough) is to inhabit them just long enough to execute some acquaintance of theirs at the behest of whatever corporate client ordered the hit. The only way back for Vos? Blow her host's brains out. No witnesses.
In a turbocharged prologue we see Vos, in the body of a hostess at an upscale restaurant, as she calmly approaches a sudoriferous VIP type and turns him into absolute sashimi. Bloodbath concluded, she puts gun in mouth but can't bring herself to do the deed. Fortunately for her, suicide by cop presents itself as an option and she wakes up gasping in her baroque hyperbaric helmet with the impassive Leigh by her side. But her inability to pull the trigger implies a less than total control over the host body. And back in the "real world", Vos struggles to gather up the threads of her own identity as she stands rehearsing her lines before a visit with her ex and their son.
This creeping dissociation reaches fever pitch as the main narrative kicks into gear. Vos's residence in the body of Colin (Christopher Abbot), unwelcome prospective son-in-law of Sean Bean's tyrannical tech tycoon, is fraught with psychic glitches as Colin's suppressed mind gropes to reassert itself. The tone becomes increasingly phantasmagoric, with epileptic flashbacks and discordant washes of color and sound, but never gets out of control. Meanwhile in the physical world, the goriness crescendos as Vos/Colin carries out her mission by means of a vicious assault with a fire iron.
Abbot's performance as a woman with a gradually weakening grip on a man's body is striking. As you'd expect, sex is a sandbox for the mind/body, man/woman question, and Abbot's sex scene with his girlfriend (Tuppence Middleton) is key, as she starts on top but Vos, feeling her way into her male form, inverts proceedings halfway through into the missionary we've already seen her adopt with her real-life ex. Fantastic original design (the Bakelite-themed mind-transfer equipment with its analogue dials), pulsating practical effects (Colin/Vos fashions a grotesque mask out of Vos's psyche), and a versatile score underpin the film's nuanced exploration of the first question the nascent human being asks itself — where I end and you begin.