Aether Storm

You draw power from the Sea of Night, conjuring a storm of magical phlogiston at a point within range. The storm fills a 10-foot radius, 40-foot-high cylinder centered on a point. When the storm appears, each creature within its area takes 8d4 force damage. A creature takes 1d4 force damage for each 5 feet they move through the storm, and if a creature ends their turn within the storm, they take 8d4 fore damage. On your turn, you can move the storm 10 feet in any direction as a  bonus action.