Aura of Entropy

Sickening energy radiates out from you in a sphere with a 30-foot radius. While the spell lasts, the sphere remains centered on you and moves with you. Each hostile creature in the sphere has disadvantage on saving throws against becoming frightened, paralyzed, poisoned, or stunned. Creatures in the sphere can't gain temporary hit points, and any effect that restores hit points to a creature within the sphere has those hit points reduced by an amount equal to your spellcasting ability modifier (minimum of 1).

-- From Kobold Press