Of course, if you ask my point of view, I think the film's account of Plott's identity has been able to draw the conclusion that he is a K-PAX man:
Plott's sudden appearance, his sudden return from a trip during treatment, Beth's departure .
My understanding is: "Robert Plott" is the parasite of this K-PAX person, and he clearly said "I can only take one person", and finally he chose the homeless "Beth" as his next parasite. Before leaving, he told the psychiatrist, "Since you've found Robert Plott, take good care of him," which meant taking care of Robert Plott, who was his last parasite and had existed in New Mexico. .
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