Deny Restoration

You attempt to interrupt a creature in the process of healing an ally.

If the target is casting a healing spell of 3rd level or lower, you cause the spell's healing to be reduced to 0, and deal necrotic damage equal to the hit points it would have healed to the spell's intended target. If the target is a creature drinking a healing consumable (such as a Potion of Healing), the healing consumable does not cause the target to regain hit points, and instead deals acid damage equal to the amount of hit points it would have regained.

If the target is casting a spell of 4th level or higher, you must make an ability check using your spellcasting ability. The DC equals 10 + the spell's level. On a success, the spell replaces all healing, as above. A healing consumable is not affected by this limitation.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the healing is interrupted if the target spell is of a level lower than the spell slot used to cast this spell.