Pirate skeletons are skeletons of dead pirates. They appear in Mutiny, and they are the twelfth enemy the player fights. The red pirates fought the pirate skeletons at the Skull Island area. The pirate skeleton soldiers wear a green bandanna. The pirate skeleton captain looked like a pirate skeleton soldier, except he wears a pirate captain's hat on top of his green bandanna.
All of the pirate skeletons were defeated by the red pirates eventually.
It is possible that the pirate skeletons were the bones of the defeated pirate boys at the Docks. At the start of the battle the red pirate captain says, "These fellas look like they could do with a good feed more than a fight mateys!". The pirate skeleton captain then retorts, "You'll have to catch us first FATTY!". If the pirate skeletons beat the red pirates, then a pirate skeleton rhymes out, "Sticks and stones may break my bones but pirates never hurt me!".
If the red pirates beat the pirate skeletons the red pirate captain says "I am rubber, you are glue!".