The Black Cat by Edgar Allan Poe

Our friendship lasted, in this manner, for several years, during which my general temperament and character—through the instrumentality of the Fiend Intemperance—had (I blush to confess it) experienced a radical alteration for the worse. I grew, day by day, more moody, more irritable, more regardless of the feelings of others. I suffered myself to use intemperate language to my wife. At length, I even offered her personal violence. My pets, of course, were made to feel the change in my disposition. I not only neglected, but ill-used them. For Pluto, however, I still retained sufficient regard to restrain me from maltreating him, as I made no scruple of maltreating the rabbits, the monkey, or even the dog, when by accident, or through affection, they came in my way. But my disease grew upon me—for what disease is like Alcohol!—and at length even Pluto, who was now becoming old, and consequently somewhat peevish—even Pluto began to experience the effects of my ill temper.
One night, returning home, much intoxicated, from one of my haunts about town, I fancied that the cat avoided my presence. I seized him; when, in his fright at my violence, he inflicted a slight wound upon my hand with his teeth. The fury of a demon instantly possessed me. I knew myself no longer. My original soul seemed, at once, to take its flight from my body and a more than fiendish malevolence, gin-nurtured, thrilled every fibre of my frame. I took from my waistcoat-pocket a pen-knife, opened it, grasped the poor beast by the throat, and deliberately cut one of its eyes from the socket! I blush, I burn, I shudder, while I pen the damnable atrocity.
When reason returned with the morning—when I had slept off the fumes of the night’s debauch—I experienced a sentiment half of horror, half of remorse, for the crime of which I had been guilty; but it was, at best, a feeble and equivocal feeling, and the soul remained untouched. I again plunged into excess, and soon drowned in wine all memory of the deed.
In the meantime the cat slowly recovered. The socket of the lost eye presented, it is true, a frightful appearance, but he no longer appeared to suffer any pain. He went about the house as usual, but, as might be expected, fled in extreme terror at my approach. I had so much of my old heart left, as to be at first grieved by this evident dislike on the part of a creature which had once so loved me. But this feeling soon gave place to irritation. And then came, as if to my final and irrevocable overthrow, the spirit of PERVERSENESS. Of this spirit philosophy takes no account.