Shell Defense: Withdraw

You can withdraw into your shell as an action. Until you emerge, you gain a +4 bonus to your AC, and you have advantage on Strength and Constitution saving throws. While in your shell, you are prone, your speed is 0 and can’t increase, you have disadvantage on Dexterity saving throws, you can’t take reactions, and the only action you can take is a bonus action to emerge from your shell.