A cranky person
Also, a tasty crustacean. Many edible varieties of crabs are available, including (my favorite) the Maryland Blue Crab, the Dungeness Crab (popular in Monterey and other Left Coast locales, and the Alaska King Crab, which tastes quite a bit like Lobster and is often served with Drawn Butter.
The Alaska King Crab used to be known as the Spider Crab, but they realized that they weren't selling any. They told the marketing consultant, "It tastes like lobster, it's cheaper than dirt (that's not the case anymore), why isn't anybody eating these things?"
The marketroid took one look at the name and said "Duh!." They said "Doh!" and now we're running a bit short on these tasty treats too.