Is Mark Hamill in Adventure Time? I think I did an Adventure Time, but I can't. for the life of you tell you what character it was. Once you start doing animation, I've done, I don't know.

Mark Hamill was Max Brallier's childhood hero. When Brallier's book series, The Last Kids On Earth, was made into a Netflix animated series, he was able to meet and work with Hamill.