Vampiric Cloak (5e Spell)
From D&D Wiki
|Casting time:||1 action|
You wrap yourself in a cloak of life-transferring energy. Whenever a creature hits you with a melee attack, they take 3d6 necrotic damage and you regain hit points equal to half the amount of damage dealt.
At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d6 for each slot level higher than 5th.