Big (1988)

In director Penny Marshall's body transference and "fish-out-of-water" fantasy, it told about a 13 year-old boy in the body of a 30 year-old man:

• in a carnival scene one evening where teenaged 13 year Josh Baskin (David Moscow) was with his parents and baby sister Rachel, he was humiliated after being told that he was too short for the "Ring of Fire" roller coaster ride - witnessed by a pretty blonde female classmate Cynthia Benson (Kimberlee M. Davis)
• by himself, he approached toward an automated, wish-granting machine known as "Zoltar Speaks"; after inserting 25 cents, suddenly Zoltar became animated with glowing red eyes and a sign lit up: ZOLTAR SAYS - MAKE YOUR WISH; he made a wish to be 'big' ("I wish I were big"); he received a card - from the strangely unplugged machine - telling him: "Your Wish is Granted" but didn't feel anything different

Making a Wish at the "Zoltar Speaks" Machine

• the next morning, Josh became panicked when he realized, in front of his bathroom mirror, that he was a full-grown, unrecognizable young adult male (now Tom Hanks as a 30 year-old); he reached into his pocket and found a 'Zoltar Speaks' card in his wallet - informing him: "Your Wish is Granted"
• Josh quickly rode his now-undersized bicycle back to the carnival grounds, but found them empty; he returned to his home in Cliffside Park NJ, where his freaked-out mother didn't recognize him and thought he was an intruder-kidnapper; to convince her of his identity, Josh pulled down his sweatpants to show her his birthmark behind his left knee, but she was even more aghast that he was wearing her son's underwear; he was forced to flee from his own house when she threateningly grabbed a butcher knife
• fortunately, at his school, he was able to convince Billy Kopecki (Jared Rushton), his next-door neighbor and best friend, of his predicament, and confirmed his identity by singing a recognizable nonsense song; Billy stole cash and some of his father’s clothes for Josh, and the two rode together on a bus to New York City - to locate the Zoltar machine so that his life could be restored; soon after Billy helped Josh to find a cheap flophouse room at the St. James Hotel, where Josh cried himself to sleep; Billy left and promised to return the next day; meanwhile, Josh's parents filed a "Missing Persons" report
• the boys' efforts at a Consumer Affairs office to locate the carnival or fair that might help reconnect them with Zoltar failed, and they were told their request required six weeks until they received results
• in the meantime, Josh successfully applied for a computer operator data-entry job at the MacMillan Toy Company, after faking his Social Security number and his resume's work history
• to assuage his distraught mother, he phoned her posing as Josh's kidnapper, and promised that Josh would soon be returned unharmed; he provided proof of his claims by answering her question about the song she would often sing to him ("The Way We Were")
• in the film's most recognizable sequence, while Josh was in the main showroom of an F.A.O. Schwartz toy store on a weekend, he happened to meet the MacMillan Toys company executive boss "Mac" MacMillan (Robert Loggia) and quickly impressed him with his childlike enthusiasm and knowledge of toys; Josh enjoyed tap dancing and foot-tapping to the tunes Heart and Soul and Chopsticks on a giant, floor-sized and mounted electronic piano keyboard; soon after, Josh invited MacMillan to join him as a crowd of onlookers watched and applauded them
• after MacMillan recognized Josh for his child-like intuition and ability to pick successful toy products, he was ultimately promoted to toy tester in charge of Product Development; however, his sudden advancement upset top-level co-workers: sexy yuppie toy executive Susan Lawrence (Elizabeth Perkins), and her competitive boyfriend Paul Davenport (John Heard)
• with his salary, Josh rented a large loft apartment and transformed it into a childlike playroom with arcade games (a pinball machine), toys, a trampoline, and a basketball hoop
• at a fancy MacMillan company office cocktail party, Josh was inappropriately dressed in a white tuxedo with sequins, and reacted to the hors d'oeuvres (miniature corn cobs) by eating them as if they were full-sized; Susan befriended him after seeing his awkwardness, and invited him to ride with her in her hired limousine to Josh’s apartment; during the ride, Josh was distracted by the limo's sunroof and kept popping out of the vehicle
• Josh experienced a confused sexual relationship with Susan when she asked to spend the night with him; she misinterpreted her sexual interest in him and agreed to a "sleep-over" in bunk beds; he agreed to share his bunk bed with her - Susan: "I want to spend the night with you." Josh: "Do you mean sleep over?" Susan: "Well... yeah!" Josh (with a guileless reply): "Well, okay... but I get to be on top!"; afterwards, Josh jumped on a trampoline with Susan (viewed through windows from outside his apartment

"But I get to be on top!"

In Bunk Beds

Trampoline-Jumping

• Paul's jealous retaliation against Josh for stealing Susan away led to Susan's break up with Paul; during a tender, simple and innocent scene in Susan's apartment, he gently touched her breast through her bra before kissing her, and they spent the night together
• Billy was finally able to receive a list of carnivals and fairs that he and Josh requested, but by this time, Josh had become completely distracted by his relationship with Susan, and he ignored and neglected Billy's demands that Josh listen to him and set his priorities straight
• in a subdued scene, Josh returned to his hometown and walked around his neighborhood and school; he noticed younger kids, including his friend Billy, having playful fun and longed to return to the simple joys of childhood; later, during dinner with Susan, Josh attempted to explain his transformation and his real age ("I'm a child, Susan, and I'm - I'm not ready for all of this"), but she interpreted his fears as a lack of commitment, and dismissed what he was saying
• ultimately, Billy was able to inform Josh of a Zoltar machine at Sea Point Park; in a daze, Josh left the toy company (in the middle of a proposal presentation), where he made a wish to become a kid again; his wish was not fulfilled until he unplugged the machine to put it back into its magical mode of operation; Susan followed after him and realized that Josh's earlier confession about his transformation was actually true, and that their relationship would be ending; she declined Josh's offer to have her use the machine to turn herself into a little girl

• in the conclusion, Susan drove Josh home, and outside his house she kissed his forehead before they parted ways; there was a poignant final shot of Susan watching Josh, who waved goodbye
• he transformed into a 13 year-old boy again (with clothes that now didn't fit him) - he ran toward his home, calling out: "Mom?...I missed you all so much"
• in the short epilogue, Josh and his friend Billy walked down the street discussing playing stick ball (to the instrumental tune of Heart and Soul)