Xanathar's Guide to Everything, pg. 160
Life Transference
3-level
Necromancy
Casting Time 1 Action
Range 30 ft
Duration Instantaneous
Components V, S
Damage Type: Necrotic
Attack/Save Throw: None
Description: You sacrifice some of your health to mend another creature’s injuries. You take 4d8 necrotic damage, and one creature of your choice that you can see within range regains a number of hit points equal to twice the necrotic damage you take.
At higher levels: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 3rd.
Class(es): Cleric, Wizard