Brittle Barrier

You touch a willing creature, surrounding them in a brittle layer of energy that protects them while harming attackers. At the beginning of each of the targets turns, they gain a pool of temporary hit points equal to 1d4 plus your spellcasting modifier. if they take damage that would reduce your temporary hit points to 0, each creature within 5ft of the target takes 1d6 thunder damage as the barrier shatters violently.

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, you deal additional damage when your barrier shatters and gain additional temporary hit points equal to 1d4 per level and 1d6 per level respectively.