What is the rarest Islehopper in Sea of Thieves?

Ahoy there, fellow pirate! I'm curious, what is the rarest Islehopper to be found in the vast and treacherous Sea of Thieves? Are we talking about a particular breed, a unique coloration, or perhaps a special variation that's harder to come by than a chest full of doubloons? I'd love to know the details, as I'm always on the hunt for rare and elusive treasures!