Dr. John A. Zoidberg is a lobster-esque alien from planet Decapod 10 and the Planet Express physician.  Zoidberg seems generally clueless about human anatomy and is kind of a homeless loser.  We love him anyway.

Dr. Zoidberg is voiced by Billy West.

Dr. Zoidberg Quotes

Zoidberg: Now open your mouth and let's have a look at that brain. No, no, no, no, no, not that mouth!
Fry: I only have one.
Zoidberg: Really?

Fry: Uh, is there a human doctor around?
Zoidberg: Young lady, I'm an expert on humans.