6. Marvin the Paranoid Android (The Hitchhiker's Guide To the Galaxy)
Here we have another that had a long history before appearing in a film. Marvin - the manically depressed robot - was created in 1978 for the radio broadcast of The Hitchhiker's Guide to the Galaxy, then later went on to appear in all five books, the BBC mini-series, and finally the big screen adaptation. He has had frequent appearances outside the series though, even having a Radiohead song named after him (see Paranoid Android from their 1997 album OK Computer). Although one thing is consistent... with nearly every appearance, he looks totally different.
