Nicole Perlman, the original screenwriter for "Guardians of the Galaxy," has never been very public about her struggle to share credit with James Gunn. But in the new book, "MCU," fellow Marvel writer Zack Stentz was willing to unpack the debacle. While Perlman is quoted as saying, "I credit everybody on that movie, including James, for making it so beautiful," Stentz sings a different tune. "Nicole had to knife-fight for her credit on 'Guardians of the Galaxy,'" he said, noting that she was the first female writer to write an MCU movie. And, according to the "Thor" writer, she was much more embittered than she let on to the public.

"She threw a party when the movie came out literally called the 'F*** James Gunn' party because she had won that very bruising credit arbitration," Stentz said. Moreover, Perlman's fellow Marvel alum claims that Gunn was deliberately trying to take the credit for himself. "The thing that I'm still angry about, and I say this as a fan of James Gunn as a director, was that he very clearly was selectively leaking stuff to his friends and the fanboy media circles to undermine her credit."

While, at the end of the day, "Guardians of the Galaxy" is a James Gunn film, with all the visual flourishes and outcast characters that define his projects, Perlman's legacy in creating the film was undoubtedly more pronounced than is often recognized. Wherever the two creatives stand today in their personal relationships, both remain remarkably successful. Gunn is now the co-head of DC Films at Warner Bros. Discovery, while Perlman is at work on the female-centric "Fast and Furious" spin-off.