''The Cat o' Nine Tails'' is a {{giallo}} film by Creator/DarioArgento which was released in the year 1971. It is the second film in his "animal trilogy".

Blind former reporter Franco Arnò and his niece Lori are walking home one night, when he overhears a conversation between two men in a car about blackmail. Later on a breaking-and-entering happens at a nearby biology research institute. He deduces that these two instances are connected, and joins up with reporter Carlo Giordani to investigate. As the two snoop around, string of murders occur, all connected to the research institute...

!!Examples in this film:

* AbsoluteCleavage: Anna's outfit when Giordani questions her about involvement in the institute business.
* AmateurSleuth: Arnò.
* BlatantLies: The killer lies to Arnò that his niece is dead before dying.
* BoundAndGagged
* CarChase: Police try to tail Giordani and Anna Terzi, but she shakes them off.
* CoversAlwaysLie: Various posters for this film feature menacing cats, often with bloodied fangs, but there are no cats in the film at all. The title refers to the large number of clues pointing towards the murderer which are likened to nine tails on a cat.
* DamselInDistress: Lori is kidnapped by the killer near the end.
* DeathByFallingOver: Dr. Calabresi dies when he is pushed on front of an oncoming train.
* DestinationDefenestration
* DisneyVillainDeath: The killer dies when pushed into an elevator shaft.
* {{Diary}}: Prof. Fulvio Terzi's diary provides some information regarding his relationships with his foster daughter.
* ExtraYExtraViolent: One of the things that the biology research institute is studying on.
* FriendOnTheForce: Spimi for Giordani.
* GoodSmokingEvilSmoking: Both Giordani and the killer smoke cigarettes.
* GrammarNazi: Arnò
* GraveRobbing: When Arnò realizes that Bianca still has a vital clue on her, he and Giordani are forced to open up her coffin.
* HandicappedBadAss: Arnò
* HiddenWeapons: Arnò has a retractable blade on his cane.
* IHaveYourWife: Niece, in this case.
* InSeriesNickname: Lori has given her uncle the nickname "Cookie".
* IntrepidReporter: Giordani.
* ManlyGay: Prof. Braun's lover Manuel.
* MistakenForMurderer: Giordani accuses [[spoiler:Anna of the murders.]]
** He also briefly suspects [[spoiler:Arnò when Arnò enters the masoleum with a bloody retractable blade at the end of his cane.]]
* PapaWolf: Arnò towards Lori.
* RainOfBlood: Arnò is able to track the killer at the institute when some blood drops on him.
* RedHerringMole: [[spoiler:Anna Terzi.]]
* TamperingWithFoodAndDrink: The killer tries to off Giordani with poisoned milk.
* TitleDrop: Done when Arnò and Giordani are going through the leads and note that there are nine of them. This is followed by an allusion to a "cat o' nine tails", a navy whip.
* TrailersAlwaysSpoil: The trailer prominently displays the killer's death.