Casper's 1000 mile step

You fire a number of spectral blue strings towards a target dealing 3d10 psychic damage, on a hit whenever the target takes a step it will feel as if they have been hurled through space at an incredible speed as they move through hidden pockets of far stretched space that eminate from them. And the target takes 6d8 force damage for every 5ft. they move. For the duration the target has disadvantage on ability checks and saving throws using Dexterity and Wisdom.