Thunder Bolt

You point your finger and a line of thunderous energy launches out from your finger when it hits it's target a sphere a thunderous energy explodes from the point. Make a each target in a 10-foot radius sphere centered on that point must make a Constitution saving throw. A target takes 1d10 thunder damage on a failed save, or half as much damage on a successful one.

This spells damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), 17th level (4d10).