4 ideas
A German bourgeois social circle receives Horacio Kalibang, a composed and enigmatic figure who moves among its members as an ordinary guest. The tale, written by the Argentine naturalist Eduardo Holmberg, is widely cited as the first Latin American science-fiction story.
If a person acts only through routine, etiquette and repeated phrases, an observer cannot distinguish them from a well-built machine. The test of being human is therefore behavioral rather than material: whatever cannot deviate from its script counts functionally as an automaton, whatever it is made of. The respectable bourgeois, who is rewarded for predictability, is the easiest person to replace with clockwork.
A single convincing automaton does more than add one fake person. It makes every real person in the room suspect, because the proof that imitation is possible removes the default assumption that others are human. The horror comes from category collapse, not from the machine being menacing.
Grounding a marvel in mechanism and invention rather than in magic turns the supernatural tale into speculative fiction. The reader cannot dismiss the event as impossible, so it unsettles them more. In this way the positivist confidence in science becomes a source of dread as well as of explanation.