Well, SOMEBODY needs to do a pirate Pokemon. After all, pirates are the first things to come to mind when you think of a warrior of the sea.
A squid's head makes a wonderful base for a pirate's hat, without actually being a hat. With multiple arms, it can pull off Fighting attacks quite easily. Of course, you'll need the trademark cutlass and hook. The front two arms can be used as fist for punching moves.
Blacking out an eye can give it the effect of an eyepatch, although whether it's necessary is the question. A skull shaped design can carry make the pirate hat look more obvious, although it may be too heavy handed.