Drakkor's Glacial Blast

A pale blue streak flashes from your pointing finger, or focus, to a creature you see within range and then blossoms with a high pitched roar into a focused explosion of ice.  The target must make a Constitution saving throw.  The target takes 8d6 cold damage on a failed save, or half as much damage on a successful one.  On a failed save, the creature also has it's movement reduced to 10 feet until the end of the caster's next turn.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, 1 extra shard of ice (1d6) is hurled back at the creature from the explosion for each spell slot level higher than 4th.