The irony in Edgar Allan Poe's story "The Black Cat" stems from his spoken love for his wife and cat and the eventual murder of both. In this story, the irony comes from a conflict between what the narrator says and does.
The narrator of this story tells the audience he's not mad, but his future actions indicate otherwise. Additionally, in the first paragraphs of the story, the narrator states, "My tenderness of heart was even so conspicuous as to make me the jest of my companions. I was especially fond of animals, and was indulged by my parents with a great variety of pets." He also claims to love his wife.
The audience finds irony between the expressed feeling of love and a deliberate act of hate. An article from the University of San Francisco notes, "With the logic of dream retribution, the murdered Pluto reappears in the guise of another one-eyed black cat who haunts the narrator in his own household and, after the narrator's murder of his wife, and his walling-up of her corpse in his cellar, brings about the murderer's arrest by police.” Poe manages to make the audience reconsider words of affection and actions of hate with this tale of love and madness.