Unhealer

You have learned to use healing spells in a damaging way, reverting previous healing instead of healing something. This can be either magic healing or natural healing, but the target has to have been damaged sometime in the past. Visible scars or past wounds can be targeted. This spell reopens scars, reactivates diseases or brings back wounds in some way or another. If the target was not damaged at all, nothing happens. If the target was not damaged as much as the spell would do, the target only takes as much damage as it has ever had.

You can use any spell with a healing effect as a damaging spell, changing its effects as following:

• The spell's school is Necromancy
• The spell loses its healing power when used this way. Whenever a target would gain hit points because of an effect from the spell, it receives necrotic damage instead.
• If the spell is a ranged spell, the target makes a Wisdom saving throw against your spell save DC. If it fails, double the dice rolls for this damage.
• If the spell is a touch spell, make a melee spell attack against the target. On a miss, the spell fails. Double the dice for this damage.
• If the spell would do more damage than the target has ever taken, the spell only does as much damage as the target has taken in the past instead. This is up to the DM's discretion.

The spell consumes a spell slot as usual.