In the Avu Observatory by H.G. Wells

A night watchman at a remote observatory encounters a terrifying, unknown creature that stalks him in the dark. As he hides and tries to escape, the tension mounts until a final, breathless confrontation. The story is brief but intensely suspenseful, focusing on fear and isolation in a scientific setting. It blends horror with speculative elements. It’s an early example of blending science fiction with primal terror.