Psychoanalysis has long paid attention to surprise. The psychoanalytic discussion of surprise includes two viewpoints, one that sees surprise as the perturbation of therapeutic systems, and another that views it as the emotion of encountering a world that is different from the one the subject expected. In this presentation, I attempt to propose an additional and new dimension of the discussion of surprise. Through clinical vignettes with a traumatized female patient, I illustrate that this sense of surprise is not one felt by already existing subjects, but a sensation felt when people discover themselves, the other and the world. Subjects, and the world, do not exist yet in that state. This feeling exhibits fluctuations, just like any other surprise. But it does not imply the perturbation of systems that have already been created. This surprise is the fluctuation of a system born at the moment of a human encounter, returning that encounter to its original starting point.