Arrow of Slaying
An _arrow of slaying_ is a magic weapon meant to slay a particular kind of creature. Some are more focused than others; for example, there are both _arrows of dragon slaying_ and _arrows of blue dragon slaying_. If a creature belonging to the type, race, or group associated with an _arrow of slaying_ takes damage from the arrow, the creature must make 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 an _arrow of slaying_ deals its extra damage to a creature, it becomes a nonmagical arrow.
Other types of magic ammunition of this kind exist, such as _bolts of slaying_ meant for a crossbow, though arrows are most common.