Callowin's Chronal Chill

You focus your mind on a 20 foot sphere that you can see within range. Pulling at the fabrics of time and space you rip open a tiny sliver between the astral sea and the material plane. Creatures that enter this area for the first time, or begin their turns in this area must succeed on a constitution saving throw. On a failed save, the target suffers 1d8 cold damage and 1d6 psychic damage. This area is considered difficult terrain as the time distorts around this astral tear. 

At Higher Levels: The damage of this spell increases by 1d8 cold damage for each level above the first. Additionally for each additional level the radius increases by 5ft.