The Sphinx (Poe)
During the cholera outbreak in New York, a man visited his relative's cottage on the banks of the Hudson River. They spent their days engaging in various activities, but the news of death and disease from the city constantly haunted them.
The man became obsessed with the idea of omens and argued with his relative about their validity.
That palsying thought, indeed, took entire possession of my soul.
One day, the man saw a monstrous creature on a nearby hill. It was larger than any ship and had a proboscis, tusks, and wings covered in metal scales. The creature also had a death's head on its chest, which filled the man with horror and dread. He fainted upon hearing the creature's mournful cry. When he recovered, he hesitated to tell his relative about the experience.
A few days later, the man finally shared his story with his relative, who initially laughed but then became concerned for the man's sanity. As they discussed the matter, the man saw the creature again and pointed it out to his relative, who claimed to see nothing. The man became increasingly alarmed, fearing that the vision was an omen of his death or a sign of impending madness.
His relative, however, remained calm and questioned the man about the creature's appearance. After hearing the description, the relative retrieved a book on natural history and read about the genus Sphinx, a type of insect with a death's head on its body. The relative then sat in the same spot where the man had seen the creature and spotted it again, crawling up a spider's thread on the window. The creature was, in fact, a tiny insect, only a sixteenth of an inch long and the same distance from the man's eye.
I found it to be about the sixteenth of an inch in its extreme length, and also about the sixteenth of an inch distant from the pupil of my eye.
The man's fear and belief in omens had caused him to misjudge the size and importance of the creature.