Arrow of Peaceful Rest

An Arrow of Peaceful Rest is a magic ammunition type meant to slay undead specifically.

If a creature belonging to the undead category takes damage from the arrow, the creature must make a DC 16 Constitution saving throw, taking an extra 2d10 piercing damage on a failed save, or half as much extra damage on a successful one.

This is in addition to the base damage of a normal arrow. 

Once an Arrow of Peaceful Rest deals its extra damage to a creature, it becomes a nonmagical arrow.

Notes: Damage: Piercing, Damage, Combat, Bane