Tiakealic's Stolen Kiss

A creature you can see makes a Constitution save. If they fail, they emit thin, red wisps of smoke as their vitality is brought to the surface. The next time the target hits another creature with a melee attack, before the spell ends, they take 6d8 necrotic damage while the creature they hit gains temporary hit points equal to half the damage dealt to the target. The spell then ends.

At Higher Levels: The damage increases by 1d8 for each slot level above 4th.