This study analyzes the transformation of Elizabeth Berry's character in May December (2023) through René Girard's Mimetic Theory, focusing on the progression from professional observation to identity appropriation. Previous studies have identified imitation, repetition, corporeal appropriation, remediation, and representational instability in the film, but the relational mechanisms that organize the intensification of Elizabeth's imitation remain relatively underexplored. This study uses a descriptive qualitative design with a theory-informed textual film analysis approach. The released film is used as the primary text, while the final screenplay is used as an auxiliary textual source. A total of 19 data units were selected purposively and analyzed through two-level coding that distinguishes descriptive evidence from Girardian interpretation. The results show that Elizabeth's pursuit is initially directed at representational authenticity, while Gracie gradually becomes a model/mediator who increasingly determines how the object is pursued. Elizabeth's engagement then progresses through embodied imitation, internalization of the model, experiential identification, and relational appropriation, until the embodied, vocal, experiential, and relational dimensions converge as multi-domain identity appropriation. However, increasing resemblance does not result in complete identification or mimetic satisfaction. The overall trajectory can therefore be read through Girardian metaphysical desire, where representational authenticity becomes increasingly model-dependent without ever being fully achieved. Based on this pattern, this study proposes unfinished mimetic appropriation as a data-grounded conceptual synthesis to explain the process by which progressive appropriation of the model's identity sustains, rather than resolves, the desire for further approximation.