Death Zero

you send your darkness to a point you can see within range and create a 30 foot radius sphere that exudes extreme pressure . Each creature in that enters the sphere for the first time or start their turn in the sphere must make a strength saving throw. On a failed save, the creature takes 6d10 force damage and is knocked prone and their speed is reduced to zero and cannot be higher then zero. the target can make an athletics check on their turn as an action against the spell casters save dc to end the effect of zero movement speed. on a successful save the creature takes half damage and is not knocked prone.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, the damage increases by 1d10 for each slot level above 6th.