From the very first sight that the man catches of the horse, it is clear that this is no ordinary horse, although initially perhaps the description of it running on its toes "like a cat, like a dog up to no good," presents it as being initially more innocuous than later evidence dictates. What changes, however, is the way that the man in the next paragraph, sees it silhouetted against the sky "like a nightmarish leopard." The use of this simile compares the horse to a beast of prey who is dangerous and fearful, which clearly adds greatly to the dramatic impact of this story as the reader, and the man, begins to realise that this horse is actually going to be a source of threat and danger to the man. This danger is crystallised when they confront each other under the tree and the horse openly attacks the man:
The horse was almost on top of him, its head stretching forward, ears flattened and lips lifted back from the long yellow teeth. He got one snapshot glimpse of the red-veined eyeball as he flung himself backwards around the tree.
The description of the horse, and how he is shown to develop from a vaguely curious creature to an antagonistic animal that is trying to kill the narrator, is used by Hughes to emphasise the theme of nature vs. man in all its distinctness. Note how particular details, such as the horrific snapshot image of the "red-veined eyeball," are used to build up the picture of the horse as a dangerous, life-threatening entity. Given that the protagonist of this story is a man who openly confesses that he has lost all connection with nature due to his immersion in the city and his career, it becomes obvious that the horse and the rain which is so strongly connected to it represent the sense of nature that the man has lost because of his work. It is the description of the horse as a dangerous beast that gives this text such power and impact.