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.