Acid Wall

You create a wall completely made of acid. you can designate people to walk through the wall without taking damage. All that are not designated take 8d8 Acid damage and loose 1d6 x 10 feet of speed for 1 minute. If this penalty reduces their speed to 0 or less, the target must succeed on a Dexterity saving throw. On a fail, they take 1d8 Acid damage. On a success, their speed increases by 10. Once they regain the speed they had originally, the penalty ends.