Dr. Powell: I'd like to begin by asking you... if you know why you're here. prot: Of course. You think I'm crazy. Dr. Powell: I prefer the term "ill". Do you think you are? Ill? prot: (shrugs) A little homesick, perhaps.
An adaptation of the 1990 novel of the same name, K-PAX is the story of a clinical psychiatrist (Jeff Bridges) who takes on a patient claiming to be an extraterrestrial from an advanced alien civilization. The patient (Kevin Spacey), named prot (rhymes with "goat" and spelled with all lowercase letters) displays vast academic knowledge and remarkable philosophical outlooks, which begin having positive effects on the patients and staff of the Manhattan Psychiatric Institute... while leading to increasing uncertainty over his true origins.K-PAX is host to scores of theories as to the exact nature of prot's character, and remains one of the definitive Maybe Magic, Maybe Mundane films to this day.
This film provides examples of:
Actor Allusion: An interesting variation - in the original novel, prot lists Starman as one of his favourite films. Starman was about a benevolent alien visitor played by Jeff Bridges. The novel, which is written in the first person by Dr. Gene Brewer as a psychological case study of prot, mentions that it's been optioned into a movie towards the end, so it's entirely possible that we're watching the same film the book's characters eventually see, Jeff Bridges and all.
Adaptation Name Change: From Dr. Brewer in the novel to Dr. Powell in the film, as Gene Brewer is the real life author.
Armor-Piercing Question: Powell objects to prot attempting to cure Howie and Ernie, protesting that it's dangerous for him to attempt it and that it isn't his job to cure them, it's Powell's. prot casually asks if it's his job to cure his patients, why hasn't he done it yet?
Artistic License - Medicine: Powell could very likely lose his license to practice medicine with how he treats prot, for just one example of why, discussing his handling of a patient with others.
Alien Among Us: Inverted - prot is completely open about his supposed nature, even with strangers, which lands him in the back of a cop car within minutes of arriving in New York City.
Alien Non-Interference Clause: prot doesn't mention an actual rule, but refuses to explain the mechanics of light-travel on the grounds that a relatively primitive species like humanity could use it as an apocalyptic weapon.
Aliens Speaking English: Dr. Powell specifically asks about this, given prot's complete mastery of unaccented, idiom-filled English. prot responds that English is not a difficult language to learn compared to his native language, the name of which alone is about ten syllables long and contains multiple grunts and clicks.
Aside from the alternate perspective of prot's true identity between film and book, the book goes much more in depth on the backstories of the other patients and Brewer himself. For instance, the film is ambiguous on Howie, while the book explains clearly he's an obsessive compulsive, thus the relevance of prot's tasks that encourage him to focus his attentions on specific matters.
prot's behavior during the hypnosis sessions is likely going to confuse those who haven't read the books, which go more in-detail and lead Brewer to conclude that the regressed prot gets confused when questioned because Robert hadn't mentally fleshed out all the details about K-PAX yet, and thus "prot" doesn't know the answers to Brewer's questions. It's for this same reason that prot's personality shifts during each session as they move forward in time and Robert gave his alter-ego more of a distinct character.
Bizarre Alien Reproduction: According to prot, the K-PAXian mating process is profoundly painful and associated with a terrible smell.
Bizarre Alien Senses: prot is confirmed early on as being able to somehow detect infrared wavelengths of light. He claims it's an evolutionary trait due to the persistently low light conditions on K-PAX. It's also hinted that he's watching Powell at one point through a two-way mirror, and he's able to understand animals.
Blue and Orange Morality: Zigzagged. prot claims every being in the universe is capable of telling right from wrong. Their mastery of this on K-PAX has created a society where no crimes are committed, no harm is payed and no laws are necessary. He later claims that the human need to punish misbehavior, "an eye for an eye," is seen as a destructive and stupid practice by most other species in the universe
Bluebird of Happiness: prot tasks his obsessive-compulsive fellow patient Howie with "finding the Bluebird of Happiness". Rather than his usual routines, Howie sits quietly in front of the windows for days, watching the trees. When the Institute is visited by a blue jay, he erupts into an ecstatic frenzy, and his joy is contagious to the rest of the patients and even the staff.
Catapult Nightmare: Powell awakens from a dream this way to the epiphany of what prot's departure date means.
Chekhov's Gun: prot keeps a journal. When his pencil falls out of his pocket during a hypnosis session, Powell picks it up without realizing it, and finds a number and letters on it that finally lead him to discovering prot's identity.
Chest Burster: When prot introduces himself to Dr. Powell, he humorously assures him that he's not going to leap out of Dr. Powell's chest.
Dr. Powell "What would you say if I were to tell you that I don't think you took any trip at all, to Greenland or Iceland or anywhere? That I don't believe you're from K-PAX? I believe you're as human as I am?" prot: "I would say you're in need of a thorazine drip, doctor."
Demoted to Extra: The other patients, compared to the novel at least. Several are not seen at all and the handful that do appear play smaller roles. This also occurs to a lesser degree to Brewer/Powell — the book contains two subplots, one where he's going through a midlife crisis and is attracted to a reporter investigating prot, and how prot reminds him of his late father that he has a lot of love/hate issues with. Neither matter is even hinted at in the film.
Gender Flip: Dr. Klaus Villars, a white, bearded, German-accented, classically Freud-reminiscent psychiatrist in the novel becomes Dr. Claudia Villars, a female black American in the film.
Higher-Tech Species: K-PAXians, by thousands, perhaps millions of years. They have advanced Faster-Than-Light Travel which is apparently available to all their individuals, who can use it without any clear or visible machinery. The novel records prot describing other technology such as holodeck-like libraries and comprehensive herbal medicine.
How Do You Like Them Apples?: In his first session with Dr. Powell, prot immediately inquires after the bowl of apples in the office, and proceeds to devour one with great satisfaction.
Human Aliens: Played with. prot claims he only looks human on Earth, because it's the most energy-efficient form to take, and likewise, on K-PAX he looks like a K-PAXian. It later ends up being a bit more confusing - he doesn't just look human, he looks exactly his human "friend" who went missing years earlier. The ambiguous implications are either that a) he simply is this person, a delusional savant, or that b) after the human's failed suicide attempt, prot's true form took over his friend's body and merged their consciousnesses.
Humans Are Flawed: prot highlights the many primitive, barbaric and dangerous aspects of the human race at its current stage.
Humans Are Special: But he also muses that Earth is full of millions of organisms, humans, plants, animals, insects, all rushing to find their place in the world, bonding with each other. No one ever misses him on K-PAX when he leaves, but he senses he will be missed when he leaves Earth, and realizes he'll miss them too.
Immortal Procreation Clause: Fleshed out more in the original novel - K-PAXians live for over a thousand years, but the painful, disgusting sexual process required to conceive K-PAXian children means overpopulation (let alone accidental pregnancy) is not an issue.
Light is Good: Played with - K-PAXian FTL travel is based on using light itself as the medium to travel by. prot displays a reverence for light, which becomes instilled in some of the characters he interacts with, especially Dr. Powell, but also has a respect and caution for its power. He refuses to explain the hard mechanics of light-travel to human scientists out of concern for our relatively primitive race using it to blow themselves or another planet up. Furthermore, he is light-sensitive by human standards and wears thick sunglasses at nearly all times, claiming that Earth is far brighter than K-PAX, where conditions are usually closer to our own twilight. Light in general is also used beautifully as a visual motif throughout the movie.
Maybe Magic, Maybe Mundane: One of the definitive examples of the trope. There's evidence that prot is just Robert's alter-ego and is a savant with surprisingly forward knowledge of astrophysics, but there's also a few mysteries about him that make it possible he is indeed an alien using Robert's body.
Napoleon Delusion: One of the patients is a woman who claims she is the Queen of England.
Riddle for the Ages: prot's true nature. By the end of the film moving and elaborate evidence has been given for both major possibilities.
The Shrink: Psychiatrist Dr. Powell is Type 2. He does want to help his patients and sees medication as a useful aide and not a universal solution, but it's evident early in the film where he doesn't fully listen to Ernie and casually tells him he needs to start sleeping again because "sleep is good!", that he has trouble connecting with his patients.
The Snack Is More Interesting: prot interrupts Dr. Powell during their first session to ask for one of the apples in a basket on the shelf, which he proceeds to noisily devour. He begins their next session by eating an entire banana in about twenty seconds, without peeling it. In his words, "Your produce alone has been worth this trip."
Strawberry Shorthand: Due to prot's love of fresh fruit, staff co-ordinator Joyce Trexler brings him a bag of homegrown strawberries from her garden.
The Stinger: The credits end with Dr. Powell, having developed an interest in amateur astronomy, standing in his backyard at night and looking at the constellation Lyra through a telescope, wondering...
The Stoic: prot is universally calm and collected.
Superior Species: K-PAXians are all vegans and live in a utopian society with no laws (as none of them would commit crimes against each other anyway).
Trademark Favorite Food: prot enthusiastically eats prodigious amounts of fresh fruit throughout the movie - peels, stems and all. According to him, K-PAXians are all vegetarian/vegan.
Trauma-Induced Amnesia: The murder of Robert Porter's wife and young daughter, followed by his murder of their killer, followed by his suicide attempt. The question is whether it turned him into a disassociative-personality delusional with savant-like intelligence, especially for astronomy, or if it was the catalyst for his lifelong alien friend prot to reunite with him.
The Unreveal: The exact nature of prot/Robert Porter's existence is never quite unraveled, though profound evidence is found for both his life as a traumatized human and background as an alien. The truth is likely a combination of both involving prot bonding with his human friend's body and mind, but this is never outright said, and left up to the audience to piece together.
Through the Eyes of Madness: When prot "leaves" in the end, the other patients comment that Robert Porter looks nothing like prot, implying they could see him for what he is.
Wham Line: Bess gets exactly one line of dialogue in the entire film, and it's a short one. But it makes it clear she's much more perceptive than she appears when she whispers to prot the following after Howie finds the Bluebird of Happiness:
"I know who you are. You're the bluebird..."
And then from Powell:
"There it is! Robert Porter, drowned! His name is Robert Porter!"