Possession is the sort of film that, even if you’ve had the whole plot spoiled for you, can be difficult to follow. Watching Adjani on screen is exhausting — She ricochets between unsettling detachment and high-octane delirium with alarming ease and speed. The third standout performance comes from Heinz Bennent, who plays Heinrich, the man Mark believes Anna is leaving him for. But in the abstract nightmare of Possession, Bennent fits perfectly, rolling around, alternately assaulting Mark and coming on to him. What starts as a slimy creature, not unlike the baby from Eraserhead, eventually becomes a doppleganger of Mark.