Arcane Joust

Charging your weapon with magical energy, with a thrust a spear of arcane power shoots forward. Each creature in a 20-foot line must make a Dexterity saving throw. A creature takes 2d6 force damage on a failed save, and gains Vulnerability to the damage type of the weapon used to cast with until the end of your next turn. (This does overcome the Resistance against non-magical weapons allowing normal damage.) On a successful save the creature only takes half as much damage. 

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot above 1st.