The Neptune's Shell is an equippable item that transforms the wearer into Merfolk when they enter water. In this state the player has the ability to breathe underwater, swim as if they had flippers, and isn't slowed down like normal. The effect instantly wears off as they leave the body of water.
- The Neptune's Shell does not work in lava, even when used in conjunction with an Obsidian Skin Potion. This is probably because one cannot drown in lava.
- If both a Neptune's Shell and Moon Charm or Moon Shell are/is equipped while the player is underwater at night, the merfolk transformation overrides the werewolf transformation.
- Oddly enough, you still transform when submerged in honey, though there is the regular slow down. This is probably because you can drown in honey.
- Wearing a Fish Bowl will not transform the player.
- The player's head moves up and down while swimming.
- If the player goes directly from lava to water, they will not transform until they leave and re-enter the water.
- Now you can hide the transformation while keeping the bonuses, or put it in the vanity slots.
- No longer craftable. Now drops from Creature from the Deep.
- Became an ingredient in Moon Shell.
- Added to the game.