The Worst Last Roles of Otherwise Great Actors

Better known as: The writer, director, and star of Citizen Kane, considered pretty much the best movie of all time
Last role: Unicron in The Transformers: The Movie
To be honest, Orson had pretty much been a laughing stock for years at this point, his career reduced to drunkenly slurring through wine commercials. But we have to give credit where credit is due: A planet-sized Transformer? Best fat joke ever.