Dabble's Oceanic Alteration

You embellish yourself with the element of water and transform into a powerful creature of the sea. When you cast the spell you regain hit points equal to 2d8 + your spellcasting ability modifier. You also gain a bonus to concentration saving throws equal to your spell casting modifier. While the spell is active you cannot cast spells and when the spell ends you cannot cast spells for 1d8 rounds. The transformation lasts until the spell ends. You choose one of the following forms to assume: The Dolphin or The Crustacean. While the spell is active you are also unable to be affected by transmutation magic.

The Dolphin. You channel the speed and precision of a dolphin, and you gain the following benefits.

•  You gain the ability to breathe both air and water.
• You gain a swimming and walking speed of 60 feet.
• You can choose to gain a natural weapon that deals 1d8 + your spellcasting ability modifier magical bludgeoning, piercing, or slashing damage, as appropriate to the natural weapon you chose, and you are proficient with your unarmed strikes.
• When you hit a creature with a weapon attack you can choose to half that target's movement speed or remove its reaction, both effects end at the end of the target's next turn.
• You can take the Dash action as a bonus action.

The Crustacean. You channel the power of a crustacean and become much more durable, and you gain the following benefits.

• You gain 2d10 + half your spellcasting modifier temp hp and your size category increases by one.
•  You gain the ability to breathe both air and water.
• You gain a swimming speed equal to your walking speed.
• You get a bonus to your AC equal to your spellcasting ability modifier.
• You grow a large crab-like pincer that are magical weapons that deal 1d12 + your spellcasting ability modifier bludgeoning damage. 
• When you hit a creature with this attack it becomes grappled and restrained, only one creature can be grappled at a time and an attack can not be made against a different creauter using the pincer.  (escape DC equal spell save DC)