Lightning Javelin

This javelin is a magical weapon. When it is hurled, it transforms into a bolt of lightning, forming a line 5 feet wide that extends out from the thrower to a target within 120 feet. Everyone on the line excluding you and the creature must make a DC13 Dexterity saving throw or take 4d6 lightning damage on a failed safe, with half as much on a successful one.

It turns back into a javelin when it reaches the target. On a ranged weapon hit, the target takes damage from the javelin as well as 4d6 lightning damage.