Temporal Vortex

Reality is torn asunder as you create a breach to the temporal plane in the space above a 30-foot sphere centered on a point you choose within range, bolts of unstable temporal energy lash out at the terrain, causing it to shift across the timeline. Each creature in that area must make a Dexterity saving throw.  A creature takes 10d8 force damage on a failed save, or half as much damage on a successful one.  For the next minute, the affected area is considered difficult terrain as unstable obstructions fade in and out from across the area's timeline: Trees may bloom and wither, crates and barrels may be shifted, lakes may form or dry, etc.