When several young boys are brutally murdered in a small southern Italian village, the superstitious locals react with ignorance and violence. All misfits are immediately suspected, such as big-city tart Patrizia, local village idiot Giuseppe, and voodoo practitioner Maciara. A cop named Martelli comes to investigate, and is rather curious about a young priest, Don Alberto, who censors the town's reading material to keep it free of corruption. No one is truly innocent in this town.
The film is Darker and Edgier than most other gialli of the time period, and Fulci himself considered it his best film.
This film contains examples of:
- Big Bad: Don Alberto Avallone is the killer.
- Black-and-Gray Morality: No one in this movie is innocent. No one.
- Chain Pain: Maciara is beaten to death with chains by an angry mob.
- Gorn: The majority of the film is very light on gore, but Maciara's beating and Don Alberto's death are surprisingly graphic.
- Gory Deadly Overkill Title of Fatal Death: Don't Torture a Duckling
- Gory Discretion Shot: The camera cuts away when the young boys are murdered, and we only see the aftermath. Averted with the deaths of Maciara and Don Alberto, which are shown in graphic detail.
- Insane Troll Logic: Don Alberto's belief that by killing children, he's saving them from becoming increasingly lustful.
- Jitter Cam: Fulci uses handheld camerawork to add to the film's bleak atmosphere.
- Knight Templar: Don Alberto is a very conservative priest. He eventually turns out to be the killer. Unusually, his delusion doesn't involve punishing the boys for supposedly having lustful thoughts; he feels that by killing them before puberty can corrupt them, he is actually saving their souls from damnation.
- Market-Based Title: While Non si sevizia un paperino does translate from Italian to Don't Torture a Duckling it has a double meaning in that Donald Duck is called Paperino in Italy and a mutilated Donald toy plays a key role in the mystery, so "Don't Torture Donald Duck" might be a more accurate translation but for obvious reasons would never be used so a more literal translation had to do even if there are no duckings to be found.
- Ms. Fanservice: Patrizia, who is introduced naked. Could also be considered Fan Disservice, since she's trying to seduce Michele, but not to him.
- Non-Indicative Name: No ducklings get tortured, though a mutilated Donald Duck doll turns out to be an important clue.
- Peek-a-Boo Corpse: The discovery of the boy's body in the well.
- Police Procedural
- Red Herring: Giuseppe the town pervert, Maciara, Patrizia, and finally Aurelia.
- Van Helsing Hate Crimes: The townspeople blame the murders on Maciara, an unpopular witch, and lynch her based on zero evidence. The murders continue.
- Who Murdered the Asshole?: Inverted. The townspeople use the string of murders as an excuse to accuse all the local outsiders and misfits of being murderers, including a witch and a mentally disabled man.