Shadow Arrow

Source: Xanathar’s Guide to Everything p. 30
You weave illusion magic into your arrow, causing it to occlude your foe’s vision with shadows. The creature hit by the arrow takes an extra 2d6 psychic damage, and it must succeed on a Wisdom saving throw or be unable to see anything farther than 5 feet away until the start of your next turn.

The psychic damage increases to 4d6 when you reach 18th level in this class.