Four Flies on Grey Velvet

When the flies start to crawl, so will your flesh...

Four Flies on Grey Velvet is a Giallo film by Dario Argento from the year 1971, and last one in his "animal trilogy".

One day, professional drummer Roberto Tobias notices a strange man clad in black, who is following him everywhere. One night he goes after the man, and as he tries to question the man, the confrontation goes very wrong as the guy ends up being stabbed by his own knife and mysterious masked person takes a picture of Roberto holding it. Soon after, Roberto starts receiving messages from that person which indicate that his life is going to become living hell, and he will be murdered at one point.

Tropes used in Four Flies on Grey Velvet include:

Abusive Parents: Killer's stepfather.
As the Good Book Says...: The Professor boasts that knows over 1200 lines from the bible. He quotes about two.
Accidental Murder: Roberto stabbing the guy who has been following him.
Bullet Time: Used when killer fires a shot at Roberto during the climax.
- Killer's death also involves slow motion.
Camp Gay: Detective Arrosio. He meets another one during his investigation.
Comic Relief: The postman.
Every Car Is a Pinto: When killer's car crashes, its engine explodes.
Evil-Detecting Dog: Roberto's cat.
Eye Remember: When Dalia dies, police extract the last thing she saw from her retina: four flies on grey velvet.
Freudian Excuse: The killer hates Roberto because he's dead ringer to her father, whom she despised because he raised her as a boy and kept on beating her when she couldn't live up to the expectations.
Gilligan Cut: When Dalia tries to get Roberto into a relaxing bath, he angrily responds that he will not. Cue to the next shot where he is sitting in a bath.
In-Series Nickname: "God" for Godfrey. Also, The Professor.
Motive Rant
Nightmare Dreams: When Mirko tells about a beheading he saw, Roberto starts to have nightmares where his head is lopped off.
Peek-a-Boo Corpse: The killer leaves Roberto's dead cat inside a cabinet for him to find.
Red Herring Mole: The crippled neighbour.
The Reveal: Two of them:
- The fact that the guy whom Roberto thinks he killed is actually still alive.
- Killer's identity, who is actually his wife Nina.
Slashed Throat: Roberto's maid Amelia thought she could blackmail the killer. She gets her throat sliced instead.
Soundtrack Dissonance: Serene music plays while the killer dies.
Spiteful Spit: Marosi spits on the killer's face before being finished off.
Sunglasses at Night: The man who keeps following Roberto around wear sunglasses at all times.
What Do You Mean It's Not Awesome?: The way the audience is introduced to Godfrey: Roberto calls him by his nickname "God", and a choir of Hallelujas start blaring the background.