Disney and Marvel Studios released the full, credited cast list for Guardians of the Galaxy to Stitch Kingdom, and in doing so, they revealed a huge spoiler for the film. For the most part, the credit list included cameos that had already been confirmed. However, while many had been guessing that Nova might have a surprise cameo in the film, it’s actually someone else from the Marvel universe that shows up.

In the end credits, there is a line that credits Steve Gerber and Val Mayerik, who are the co-creators on none other than Howard the Duck. Yes, Howard the Duck evidently has a cameo in Guardians of the Galaxy. How Howard the Duck will cameo in the film is unknown. It could be anything from Peter Quill reading a Howard the Duck comic book or watching the Howard the Duck movie to Howard the Duck appearing as one of the aliens in the film.

Much has been made of who Nathan Fillion will play. Rumors had suggested the possibility of either Nova or Cosmo, but he is neither. Fillion will be made up as a ‘Monstrous Inmate.’ It will be interesting to see if he is even recognizable in his role.

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