Rare should introduce a new skeleton for each of the subtypes. They could be infrequent, random spawns, or Captains, or both.
Gold Golem: Layered in even thicker, armor and wielding an over-sized cutlass in each hand. Immune to swords and bullets. The only way to kill him is with gunpowder or cannon blasts.
Shadow Fiend: Large and somewhat amorphous, this ethereal skeleton is actually invisible at night. Only visible in close lantern light, where his elongated, claw-like appendages are most deadly. Even in the daylight, he is impossible to hurt except when illuminated by a lantern.
Merrow Skeleton: There's no safety in deep water from this skeleton. Not only is it quicker to heal in the water, but it can swim as well as any pirate. You'll have to swim far and fast if you want to escape the Merrow.
Grenadier: Fast, tough, and with a knack for hanging back, this skeleton lights short fused grenades and tosses them from range. His bombs do radius damage and can cause injuries (twisted ankle effect). If you time your shot just right, you can blow him up with his own grenade.
Like most people, I'm super excited for the time when Rare introduces some non-skellie baddies to fight on land, until then, these would be a cool addition too.
