A seemingly simple wooden mask, it holds a much darker secret. It contains the soul of a dead folk hero of the Zora. The mask allows the user to transform into a Zora, a tall sleek humanoid aquatic creature. It transforms their clothes and armor into facsimiles based on Zora culture. The transformation gives them the following bonuses and abilities:

Zora Anatomy

You gain a movement speed of 60ft in the water and the ability to breath underwater.

Zora Barrier

Zoras have a natural electostatic defense. When a creature within 5 feet of you that you can see hits you with an attack, you can use your reaction to cause the creature to make a Dexterity saving throw. The creature takes 2d8 lightning on a failed saving throw, and half as much damage on a successful one.

Zora Torpedo

While underwater the user can use their speed to their advantage, and charge into enemies. As a bonus action the user rolls a DC15 Athletics or Acrobatics check, on a successful roll the user can move to an enemy within 20 ft and make as melee attack with a weapon. Additionally they add 3d6 bludgeoning damage to the roll. This can be used once a day.

Sharp Zora Fins.

Unarmed strikes now deal an additional 1d8 slashing damage. 

Shockingly Smooth Skin.

Takes double lightning damage.

Sentience. 

The mask is a sentient lawful neutral item with an Intelligence of 14, a Wisdom of 12, and a Charisma of 19. It has hearing and darkvision out to a range of 60 feet.

The mask can speak, read, and understand Common, and can communicate with its wearer telepathically even when not worn. Its voice is light and echoing. While you are attuned to it, the mask also understands every language you know. It can share with its wearer relevant memories of its life to provide context for its knowledge. 

Personality.

The soul inside the mask is a Zora Hero who was once known as Mikau who hailed from a town in a cape of the Great Bay.  The pirate minions of a terrible sea monster had stolen seven unhatched eggs of his people and he was tasked with retrieving them. Legend tells that he confronted the pirates in their fortress and defeated their First Mate, rescuing four of the eggs. The other three had already been taken to the lair of this sea monster, and so he went braving the storm surrounding this temple island lair. There he defeated the remaining pirates and their Captain rescuing the last eggs. He then endeavored to slay the sea monster, suffering a grievous wound to his side. He returned to the cape town and gave the remaining eggs back to his people and there succumbed to his wounds. 

Only Mikau knows the real story of what happened. 

Mikau is generally laid back and would rather talk his way out of a situation than fight.