Il nido del ragno

This one starts off pretty slow. After a brief scene involving two boys playing, a man is sent to Budapest to investigate what is going on with a professor there who was supposed to have sent something. It starts to pick up once he gets there and meets the professor. The professor is a nervous man who slips him something once his wife leaves. The investigator says he'll come back later that night to talk more. When he does, the police are there, and it seems some of the people he met may not have been who he thought.

Clearly the movie had a budget. It has lots of locations, some nice special effects, and camera-work that involves cranes.

What seems initially to be a giallo movie (and arguably still is) becomes a bit more supernatural than is usual for that subgenre. There's a woman with enormous strength, an exhibitionist research assistant, an old man with a warning, spider-shaped scars, heavy rolling balls, and it just keeps getting stranger. Some good murder set pieces, and a totally bizarre climax. The ending was pretty satisfying.