Nevertheless, the encounter with Coppola has had a profound effect on Nathanael, driving him toward a gloomy mysticism which bores Clara and leads to their gradual estrangement.
He finds his student lodgings destroyed by fire, though his possessions were rescued by his friends and moved to a new house which is opposite that of Spallanzani.
However, it turns out that Coppola has lenses and spectacles to sell, and also small telescopes, and Nathanael buys one of these from him to set matters right after his earlier outburst.
As Coppola leaves, Nathanael becomes fixated on watching Olimpia through his telescope, although her fixed gaze and motionless stance disconcert him.
Coppola, who is now revealed as Coppelius in truth, wins the struggle, and makes off with the lifeless and eyeless body, while the injured Spallanzani urges Nathanael to chase after him and recover the automaton to which he has devoted so many years of his life.
Spallanzani recovers from the encounter, but is forced to leave the university because of the sensational revelation of the trick he had played in trying to pass off an automaton as a living person.
The narrator adds that the story of the automaton had a widespread effect on society, with many lovers taking steps to ensure they were not enamoured of puppets but of real flesh and blood.
Many years afterward, the narrator concludes, it is said that Clara was seen with a kind-looking man sitting before a country house with two lovely boys, and thus found the domestic happiness that Nathanael could never have provided.
The story contains an example of a horrific depiction of the folklore character, the Sandman, who is traditionally said to throw sand in the eyes of children to help them fall asleep.
The following excerpt is from an English translation of the story: Most curious to know more of this Sandman and his particular connection with children, I at last asked the old woman who looked after my youngest sister what sort of man he was.
He is a wicked man, who comes to children when they won't go to bed, and throws a handful of sand into their eyes, so that they start out bleeding from their heads.
The text clearly leaves the decision open inasmuch as it offers two understandings: that of Nathanael's belief that there is a dark power controlling him, and Clara's postulation (together with Lothar) against this that this is only a psychological element.
Of central importance is the "eyes" theme (interpreted by Freud in his 1919 essay "The Uncanny" as fear of castration), the "steps", the robot, and laughing.