Vampiric Weapon

4th-level necromancy
Casting time: 1 action
Range: Touch
Target: --
Components: V, S, M (a vial of vampire blood, which you pour over the weapon)
Duration: Concentration, up to 1 hour
Classes: Sorcerer, Warlock, Wizard
Subclasses:

You imbue a weapon you touch with a thirst for blood. Until the spell ends, the weapon gains a +1 bonus to attack rolls and deals an extra 1d6 necrotic damage on a hit. If the target of an attack made with the weapon attack isn’t an undead or construct, the weapon’s wielder regains a number of hit points equal to the necrotic damage dealt.

If the weapon isn’t already a magic weapon, it becomes one for the duration. If it is already magical when you cast this spell, and part of its magical properties is granting a bonus to attack rolls, you use your choice of either the weapon’s bonus or this spell’s, not the combination.

At Higher Levels. When you cast this spell using a spell slot of 6th or 7th level, the bonus to attack rolls increases to +2 and the extra damage increases to 2d6. When you use a spell slot of 8th level or higher, the bonus to attack rolls increases to +3 and the extra damage increases to 3d6.