Bestial Awakening

The feral world calls to your soul, howling for you to join it. You can give in to the call and transform into a beast, but the touch of silver bites you more deeply than the sharpest fang.

Beast Skin.

You always have the Polymorph spell prepared. You can cast it once without a spell slot or spell components but can target only yourself, and you regain the ability to cast it in that way when you finish a Long Rest. You can also cast it using slots you have of the appropriate level. Intelligence, Wisdom, or Charisma is your spellcasting ability for the spell when you cast it without a spell slot (choose the ability when you select this Dark Bargain).

Searing Silver.

Damage from Silvered Weapons ignores any Resistance or Immunity to damage you have. If you take damage from a Silvered Weapon or touch silver with your bare skin (or its equivalent), you can’t regain Hit Points until you finish a Short or Long Rest.