This spell allows you to reverse the healing energies of a creature, this includes natural regeneration abilities, healing spells and potions, but does not include natural resting. You can target a single creature that is visible and within range. The target is unaware of the spells effects (so it will not avoid drinking a healing potion if it would normally be inclined to do so). The next time the target creature attempts to gain HP before your next turn, it takes that much necrotic damage instead. This will not reduce it to less than 1 HP.