You create a large ethereal crustacean form around your body, which protects and aids you in combat. For the duration, your Armor Class becomes 20 (if it wasn’t already higher), you gain a swimming speed of 40 feet, and you gain blindsight out to a range of 30 feet. In addition, you can use your bonus action to make a melee weapon attack using your claws. This attack uses your spell attack bonus and deals (1d10) bludgeoning damage on a hit.   Additionally, your ethereal shell has a damage threshold of 15 hit points. A damage threshold gives you immunity to all damage unless it is an amount of damage equal to or greater than the threshold value, in which case you take damage as normal. Any damage that fails to meet or exceed the shell’s damage threshold is considered superficial and doesn’t reduce any hit points.