Ghost Pirates of the Sea-erra Madre

You swim through the boring looking hole and find Nerita digging at the ground.

"What is it?" you ask.

"Buried treasure!" she excited responds.

As you swim closer you can see a human skeleton lying on the sea floor nearby. Suddenly it jumps up and starts to move threateningly towards you.

"Look out!" you cry to Nerita who leaves the hole and swims over next to you.

The skeleton brandishes an ancient looking axe that you think could seriously injure you.

The skeleton has stopped moving towards the two of you, so you could just leave, but you really want to find out what it's guarding.