The story masterfully shifts the source of horror from the external (a snake) to the internal (a man’s mind). Pope’s terror is real, but its cause is delusion.
Harry believes he is in control of his environment (the bungalow, the empire), but he is actually paralyzed by chaos (the snake, his own fear). The story strips away his dignity, showing that his stiff upper lip is merely a facade for deep-seated ugliness. roald dahl poison pdf