In Big, Josh tries to convince Susan to become a child with him. After wishing to become an adult, 12-year-old Josh Baskin struggles to live in an unfamiliar grown-up world, eventually finding work at the toy company MacMillan Toys. There he develops a relationship with Susan Lawrence, a company executive who believes Josh is an adult man named Josh.
When Josh discovers the Zoltar machine that granted his wish, he decides to return to childhood. Susan follows him to the carnival, where Josh explains that he is really a boy and suggests that she use the machine to become a child too. Susan declines, recognizing that their relationship cannot continue once Josh returns to his real age.
The film was released in 1988, directed by Penny Marshall, and stars Tom Hanks as the adult Josh and Elizabeth Perkins as Susan. A common mix-up is Billy, Josh’s best friend: Josh convinces Billy of his identity, but Susan is the person he asks to become a child with him.