Mind Blight

Mind Blight 4th-level necromancy Casting Time: 1 action
Range: 30 feet
Components: V, S
Duration: Instantaneous
Psionic energy washes over a creature of your choice that you can see within range, draining moisture and vitality from it. The target must make an Intelligence saving throw. The target takes 9d6 psychic damage on a failed save, or half as much damage on a successful one. This spell has no effect on undead or constructs.
If you target a creature with less than 9 Wisdom, it makes the saving throw with disadvantage, and the spell deals maximum damage to it.
If you target a creature with less than 4 Intelligence, it doesn’t make a saving throw; it simply withers and dies.
If a creature dies from this spell, it becomes a Blightling, a form of Psionic Parasitic Ghoul creature. Only a spell like Wish or True Reserrection can restore someone turned to undead like this to life. A Blightling created this way is bound to serve the caster's verbal commands for a number of years equal to their Spellcasting attack bonus.
At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each slot level above 4th.