Chromatic Storm

You create a storm of energy on an area in a 20-foot radius Sphere centered on a point within range. Choose Acid, Cold, Fire, Lightning, Poison, or Thunder for the type of storm you create. Each creature in the Sphere makes a Constitution saving throw, taking 5d8 damage of the chosen type on a failed save or half as much damage on a successful one. A creature also takes this damage if it enters the Sphere or ends its turn there or if the Sphere moves into its space. A creature takes this damage only once per turn.

On your later turns, you can take a Magic action to teleport the Sphere up to 30 feet. 

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 4.

(Original homebrew by Inspired Arcana)