Your Wisdom increases by 2, and your strength increases by 1.

Your carapace provides relative armor. When you are not wearing armor, your AC is equal to 12 plus your Dexterity Mod.

You can only breathe water, being able to hold your breathe for a number of hours equal to 2 times your Constitution modifier (minimum 1 hour).

Your hands still contain the claw-like power of your ancestors. You have advantage on saves against being disarmed, losing your grip, and advantage on grapple checks.

You're biologically immortal, meaning that as long as you can shed your carapace, you are able to keep growing and living. Every 50 years past 200, you must succeed an Athletics check to shed your carapace. The DC starts at 6, and increases by 2 each time. On a success, your Strength and Dexterity score permanently drop by 1 (minimum of 3), and your Wisdom and Intelligence score permanently increase by 1, with no cap. On a fail, you suffer 2 levels of exhaustion that cannot be removed.