Not only is it a one-joke characterization, the joke is on the level of a below-average knock-knock joke.
* This filmography is not intended to be a comprehensive list of this artist’s work. Instead it reflects the films this person has been involved with that have been reviewed on this site.
As the quaintly anachronistic title suggests, "The Imaginarium of Dr. Parnassus" is as whimsical and rickety as any Terry Gilliam contraption -- an apparent labor of love, and not just for its star Heath Ledger, who died during production, but for the smoke-and-mirrors tomfoolery that goes into the construction of illusions. Another of Gilliam's charmingly antiquated, hand-crafted thingamadoodles, this one gets off to a bit of a slow start -- trying to set up too many stories... but spinning too many stories, and keeping track of them all, is also a good part of its subject.
Ledger's untimely death unavoidably became another element, since he hadn't finished filming his central role at the time of his demise. Gilliam, as you probably know, figured out a way to complete the film with three other actors -- Johnny Depp, Jude Law and Colin Farrell -- stepping in to complete the part. Once you're watching the movie, that no longer seems like such a strange or desperate move, but I'm not going to tell you how or why it works. (Remember that Natalie Wood died during the filming of "Brainstorm" and Brandon Lee in a production accident on the set of "The Crow," but those two pictures were completed, for better or worse. David Lynch's "Mulholland Dr." was a failed TV series pilot that wasn't released theatrically until Lynch said he dreamed an ending for it.) A title card at the end announces it as a presentation of "Heath Ledger and Friends."