Demonic Mantle

Using a connection with the Abyss, you summon the power of a demon to reside within you.

Make a Wisdom saving throw. If you succeed, the Demonic Mantle takes effect for the duration with you in control.
If you fail, your character is controlled by the DM for the duration of the spell. You may repeat this saving throw at the end of each of your turns.

You gain a natural weapon dealing 3 d10 bludgeoning, disadvantage of stealth, vulnerability to radiant damage, a natural armor class of 15 + DEX, and 30 temporary hit points for the duration