Enfeebling Arrow
You weave necromantic magic into your arrow. The creature hit by the arrow takes an extra dice:2d6|noform|noparens|avg (2d6) necrotic damage. The target must also succeed on a Constitution saving throw, or the damage dealt by its weapon attacks is halved until the start of your next turn.
The necrotic damage increases to dice:4d6|noform|noparens|avg (4d6) when you reach 18th level in this class.
Sources
Xanathar’s Guide to Everything p. 29