Your Strength and Constitution Scores both increase by 2

Giant Crabs are generally taller than your average man and can be anywhere from 6 to 8 feet tall and about just as wide. Your size is medium.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

While you are incapable of wearing armor, your shell grants you plenty of protection from threats. Your AC is equal to 15 + Your Dexterity Modifier. You also have immunity to piercing damage and resistance to acid damage

You might think having pincers instead of hands would be a problem. But you don't need hands, your Claws work just fine. Your Claws count as Natural weapons and deal slashing damage equal to 1d8 + Your Strength Modifier. You can attempt to grapple a creature or object with either of your Claws as a bonus action and have advantage on checks to initiate or maintain a grapple. When grappling a creature or object, you can use an attack action to put the squeeze on the creature youre grappling. This crush attack deals bludgeoning damage equal to 1d10 + your strength modifier and deals double damage to objects. This damage increases to 2d10 at 5th level, 3d10 at 11th level and 4d10 at 17th level

Your arms have a reach of 10ft and you may treat any weapon you are using as if it has the reach property. In addition, you can hold weapons with the two handed property in only one of your claws.

Climbing costs you no extra movement. In addition you can climb difficult and featureless surfaces and upside-down on ceilings without needing to make an ability check

You have an innate burrowing speed of 10 feet

You can breathe in both air and water