Sword of Life Stealing
Weapon (any sword), rare (requires attunement)

When you attack a creature with this magic weapon and roll a 20 on the attack roll, that target takes an extra 3d6 necrotic damage, provided that the target isn’t a construct or an undead. You gain temporary hit points equal to the extra damage dealt.

Roll20 Note: This is a template for creating custom items and does not have full drag-and-drop capability.