Deep Magic Volume 2 (p.233)
Undead Syphon
2-level Necromancy
Casting Time: 1 action
Range/Area: 30ft.
Components: Verbal, Somatic
Duration: Instant
Attack/Save: WIS Save
Damage/Effect: Radiant
An Undead you can see within range must succeed on a Wisdom saving throw or take radiant damage equal to 2d8 + your spellcasting ability modifier. You regain hit points equal to that amount.
At higher levels: When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for each slot level above 2nd.
Available for: Cleric, Wizard