Chromatic Sphere

You summon a 1 foot sphere of ever changing color. You have complete control over this sphere for 1 turn. You may expend a bonus action to move the sphere up to half your movement speed. Choose one type of damage for the sphere to do. Acid, cold, fire, lightning, poison, or thunder. This type of damage persists through all turns active, and deals 5d10 of the chosen type. Target must make a Dexterity save equal to your spell attack DC.