Chronal Cannon

You fire a small copper hedron from your palm, accelerated by electricity and a twist of chronal magic. The projectile travels at incredible velocity, passing through any large or smaller creatures in its path, dealing 4d6 force and 4d6 lightning damage and knocking them prone on a failed Dexterity save. 

The projectile cannot knock prone nor pass through huge or larger creatures, but will pass through thin cover. Each creature that passes the Dexterity save will take half damage.

At Higher Levels. When you cast this spell using spell slots of 4th level or higher, the damage increases by 1d6 force for each slot level above the 3rd.