Wall of Abyssal Poison

You create a wall of poisonous fog on the ground at a point you can see within range. You can make the wall up to 20 feet long, 10 feet high, and 10 foot thick, or you can make a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall vanishes when the spell ends. The wall’s space is difficult terrain. Ranged weapons have no disadvantage on the attack roll and the area isn´t obscured.

When the wall appears, each creature within its area must make a Dexterity saving throw. On a failed save, a creature takes 5d8 poison damage, or half as much damage on a successful save. One side of the wall, selected by you when you cast this spell, deals 5d8 poison damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The other side of the wall deals no damage.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.

Extra 1: When a fire source (burning arrow, fire magic et cetera) comes in contact with the wall, the Wall of Abyssal Poison disappears in a (slight) explosion. The explosion deals each creature in the contact area 5d8 fire damage.

Extra 2: When a water source (water magic, rain et cetera) comes in contact with the poisonous wall, the Wall of Abyssal Poison disappears in a acidic splash. The splash deals each creature in the contact area 5d8 acid damage.