"Gerald's Game," a novel by Stephen King, was considered unfilmable primarily due to its intense psychological elements and the confined setting, which centers around a woman handcuffed to a bed after a sex game goes wrong. The story relies heavily on internal monologue and character introspection, making it challenging to translate into a visual medium. Additionally, the graphic and disturbing themes, including trauma and survival, posed significant challenges for filmmakers. However, the 2017 Netflix adaptation successfully captured the essence of the story, showcasing creative storytelling techniques.

In the movie "Gerald's Game," the serial killer is revealed to be a character named "The Moonlight Man," whose real name is revealed to be Donnie. He is portrayed as a creepy figure who appears during the film's climax. The story follows Jessie, who is left handcuffed to a bed after her husband dies unexpectedly, and she encounters both psychological and supernatural horrors, including her confrontation with Donnie. The character is based on a creation from Stephen King's novel of the same name.