Decaying Aura

You taint the very air around you with negative energy, causing creatures around you to rot from healing magic.

All creatures within 15 ft. of you must make a Constitution saving throw when they are healed by magical means, including consuming potions. On a failure, instead of healing, the targets take 4d12 necrotic damage. On a success, the target regains hit points, but only half as much as they would normally.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, a creature takes an additional 1d12 necrotic damage on a failed saving throw per level of spell slot above 4th.