Decaying Smite

The next time you hit a creature with a melee weapon attack during the spell's duration, your weapon is cloaked in dark shadows, and the attack deals an extra 1d6 necrotic damage to the target and eats away at the wound. The target must make a Constitution Saving Throw or become unable to heal by any means for the remainder of the spells duration or until you lose concentration.

Casting this spell at a higher level adds an additional 1d6 necrotic damage per level above level 2.