Blue Gorillas

Blue Gorillas, nicknamed by the Impel Down guards and prisoners as Blugori, are large masked gorilla-like beasts with skulls painted on where their faces should be and with mechanical-like fingers. They act as guards and food gatherers for the prison by hunting the nearby Sea Kings. They all look relatively the same and each carries a large doubleheaded axe. They are all extremely strong and expert swimmers. Because they do not shed tears, are immune to pain and specially because of their mechanical fingers it's probable that they are actually cyborgs.

They were first seen chopping up a Sea King to bring in meat. When Buggy escaped they were assigned to chase him and Luffy (unintentionally). Buggy was not able to even faze one of them, but Luffy managed to defeat five.