Caelan's Shield Wall

Conjuring up an arcane barrier, you create a wall of energy that not only protects those behind it, but harms those directly in front of it.

You create a translucent wall of arcane energy 15 feet wide and 10 feet tall in front of you that moves with you. All creatures within 5 feet of you gain total cover from the shield wall. When an attack hits the shield wall or it takes AOE damage, you must make a Concentration check as if you had taken the damage. 

Additionally, when a hostile creature starts its turn within 5 feet of the front of the shield wall or moves there for the first time on their turn, spears made of arcane energy thrust towards it. The creature must succeed on a Dexterity saving throw or take 6d8 magical piercing damage on a failure, or half as much on a success.