Slasher's history is more complex than it seems at first glance. Particularly with reference to its birth, with some pointing to Pepping Tom, others referring to Psycho, and many agreeing it is Black Christmas. Three years before this, Mario Bava, the iconic giallo director, used many of the trademark elements of the genre in this film, which was also his most violent.
I have only seen a few of his work, but this has much bigger body counts with some scenes that will be remade on some classic slashers as the "bed stabbing" (Friday the 13th), though this one takes place while a couple is having some fun together. There is something truly delightful in the makeup work of the…