Poseidon’s Gift

Relical Potion

You can breathe underwater and you can use the Swim Speed as your Base Speed. You are also in fast terrain while underwater.

In addition, you also gain resistance to cold damage.

Once per Short or Long rest, you can also transform into a Shark, as if by the effect of the Polymorph spell. 

Potions

Potions can be crafted with Alchemist’s Tools and grant unique effects when consumed.

As an Action, you can consume 1 Potion or apply it to any willing creature within 5 feet, using a free hand.

Alchemist's Potions Table
Potion Type Type of Alchemical Needed Check DC
Common Potions
Common Alchemical
10
Uncommon Potions
Common Alchemical
15
Rare Poitions
Magical Alchemical
15
Very Rare Poitions
Magical Alchemical
20
Relical Potions
Relical Alchemical
25
Elysium's Door