Arrow of the Nine Hells

Infernal Ammunition 
Forged from the same stone of the castles throughout the Nine Hell’s, this ammunition burns at the soul of its target. In addition to regular damage, the target takes 3d8 psychic damage. 
- A wall of immense fire rises from the ground starting at the the end of your barrel. You can make the wall up to 50 feet long, 15 feet high, and 1 foot thick. You can shape the wall in any way you choose so long as it makes one continuous path along the ground. The wall lasts for 1 minute. 
- When the wall appears, each creature within its area must make a Dexterity saving throw. 
- A creature takes 3d8 fire damage on a failed save, or half as much damage on a successful save. Creatures that pass through the fire make another Dexterity saving throw, suffering 3d8 fire damage on a failed save, or half as much damage on a successful save. 
- Arrows, bolts, and other ordinary projectiles launched at targets behind the wall are destroyed by the fire and automatically miss. (Boulders hurled by giants or siege engines, and similar projectiles, are unaffected.) Creatures in gaseous form can't pass through it.