Avengerang (Akshan Q)

You throw a magical boomerang in a straight line, striking all creatures in its path until it hits a solid obstacle. Make a ranged spell attack against each creature in the line. On a hit, a creature takes 2d6 piercing damage. If the boomerang hits a creature, it continues 10 feet further in the same direction.

At the end of your turn, the boomerang returns to you, retracing its path. Make a ranged spell attack against each creature in the return path. On a hit, a creature takes another 2d6 piercing damage.

Using a Higher-Level Spell Slot. The damage of both the initial and the return of the orb increase by 1d6 for each spell slot level above 2.