Arrow of Slaying
Weapon,
Very Rare
(cost 8000 gp)
Crafting Components
Piece of flint from a stream in primeval forest
A particular kind of creature is chosen when this magic arrow is created. When the arrow of slaying damages a creature belonging to the chosen type, heritage, or group, the creature makes a DC 17 Constitution saving throw , taking an extra 6d10 piercing damage on a failed save, or half as much extra damage on a successful one. Once the arrow of slaying deals its extra damage to a creature, it loses its magical properties.
Other types of magic ammunition of this kind exist, such as bolts meant for a crossbow, or bullets for a firearm or sling.
Source