Arrow of Bone

To cast this spell you require a nonmagical arrow or ammunition crafted from the bone of a mummy, wight, ghast, or similar undead creature. You inscribe it with runes of death and imbue it with the essence of destruction.

A ranged weapon attack made with this ammunition gains a +3 bonus to attack and damage rolls. On a hit, the target takes 7d8+20 necrotic damage in addition to the normal damage. A successful Constitution saving throw reduces the necrotic damage by half. Hit or miss, the ammunition is destroyed. This spell ends if you cast it again while the first piece of ammunition remains unused.

Adapted from 3e's Complete Arcane.