Crustacean Claws

You invoke an old shamanistic rite to transform your hands into claws.  Choose whether you wish to transform one or both of your hands.  A hard shelled claw like that of a lobster or crab grows around your hand, with a powerful hinge and sharp inner teeth.  While a hand is transformed in this way, it can not be used to wield weapons, operate tools, or perform fine functions that require fingers.

As part of casting the spell, make a melee spell attack against a creature within the range of your normal unarmed strike.  On a hit, the creature suffers 2d4 piercing or bludgeoning damage (your choice) and becomes grappled by the claw, if it is no more than one size category larger than you.  Each claw can only grapple one creature in this way at a time.  To grapple a creature one size category larger than you in this way requires both claws.  A creature grappled by this spell takes 1d4 piercing or bludgeoning damage (your choice) at the end of each of its turns.  As an action on its turn, a grappled creature can attempt to break the grapple by rolling a Strength (Athletics) or Dexterity (Acrobatics) check against your spell save DC.

For the duration, you can repeat this attack as an action.