Bolstering Breath of Decay

You vomit forth a nimbus of foul gas that clings to your target.   The target attempts a Constitution Saving Throw; taking half damage on success.  On failure, the target takes 2d10 necrotic damage; healing you for half the damage taken (to a minimum of the caster's INT modifier).

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d10 for each slot level above 2nd and the healing by +1 per spell slot higher.