Arcane Comet

When you damage a creature within range with a spell, you can cast this spell to unleash a burst of arcane energy that flies out and strikes one of your previous targets. The target creature must succeed on a Dexterity saving throw or take 1d4 force damage.

At higher levels. This spells damage increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4).