Something of an overlooked classic of Dallamano's 70s films and one of the more impressive and memorable of the supernatural possession filone of the period.
Loved this one, the atmosphere of phantasmagoric Argento is one of my favourites in all filmdom. The feel of the opening, and later, sequences of a young girl (Fiore Argento & later Jennifer Connolly) exploring the mountainous 'Swiss Transylvania' to the stains of Bill Wyman accompanied by some excellent atmospheric wind noise have stayed with me for years. Argento excels at Fairy Tale logic and this one has it in spades, from a maggot-covered homunculus to a razor-wielding chimpanzee, so many unforgettable images! I just finished going through the recent Arrow release and it only helped to deepen my appreciation for this most unusual of slashers.