Arrow of Slaying is a very rare ammunition in D&D 5e. It does not require attunement.
Weapon (arrow), very rare
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.
Frequently Asked Questions
An arrow of slaying is a magic weapon meant to slay a particular kind of creature.
The Arrow of Slaying is a Very Rare magic item in D&D 5th Edition.
The Arrow of Slaying is a Ammunition — Weapon (arrow), very rare.
No, the Arrow of Slaying does not require attunement and can be used immediately when held or worn.