Arcane Cannon

You meld together a collection of metal scraps, creating a 3-foot long mechanical cannon that hovers within range for the duration, fueled by magical energy. When the mechanical cannon is first constructed, the cannon fires a beam of judgment out from it in a direction you choose. The beam is 60 feet long and 5 feet wide. Each creature in the line must make a Charisma saving throw. A creature takes 5d10 radiant damage on a failed save, or half as much on a successful one. Until the spell ends, you can use a bonus action on each of your turns to move the cannon up to 20 feet to a spot you can see and repeat this attack in the same direction or a different one.

At Higher Levels: The damage increases by 2d10 for each slot level above 7th.