You gain the following benefits.
You have Resistance to one of the following damage types (choose when you gain this feat): Necrotic, Psychic, Radiant, or Thunder.
When you would fail a saving throw against a spell or magical effect, you can roll 1d6 and add the number rolled to the save's total, potentially turning the failure into a success. You can use this benefit a number of times equal to your Proficiency Bonus, and you regain all expended uses when you finish a Long Rest.