Nature, as a primal force rather than a neutral constant, is often presented as overtly hostile in fiction; Ted Hughes uses the title animal in "The Rain Horse" as a metaphor for the bewildering and incomprehensible tendencies of nature. As the unnamed protagonist returns to his childhood home, he is accosted by a strange black horse that seems to stalk him with intent:
Before he was aware of anything the ground shook. He twisted around wildly to see how he had been caught. The black shape was above him, right across the light.
Obviously, the horse had been farther along the hedge above the steep field, waiting for him... he need no longer act like a fool out of mere uncertainty as to whether the horse was simply being playful or not. It was definitely after him. He picked up two stones....
(Hughes, "The Rain Horse," Amazon.com)
As he struggles to survive the horse's apparent attacks, the man has no way of knowing how or why the horse has chosen him. It seems to have no purpose beyond the attack, and when he fights back it shys away and leaves him alone. If the attack is real, and not in his head, it shows the violent side of normally domesticated animals, who act with instinct rather than reason. Nature, in this example, does not care -- or even have the capability of caring -- for a single man's life, and the instinct of the horse is either violent from an unknown derangement or from a need to protect its territory.