Brightleaf's Instant Artillery

You conjure forth a medium sized animated brass cannon, The cannon has four functional legs and and a speed of 20ft. As a bonus action you can command the cannon to move up to its speed and fire.The cannon's range is 60 ft and its cannonball burns with the brightness of phosphorus. Each creature within 10 feet of the point where the cannonball explodes must make a Dexterity saving throw. A creature takes 3d8 radiant damage and is on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 4th.