Time Wave

You launch a focused blast of energy at a creature within range, sending it's mind hurtling through past and future alike, hurting it's psyche. You make a ranged spell attack against a creature. On a hit, the target takes 1d8 psychic damage and it's speed is reduced by 10 feet until the start of it's next turn. The damage increases by 1d8 at 5th, 11th, and 17th level.