Barrier of Ozarkus

On a reaction if an ally you can see within 30 feet is hit by an attack roll or targeted by the Magic Missile spell, a layer of translucent crystal envelops an almost alien force to protect your ally., until the start of their next turn, the target has a +5 bonus to AC, including against the triggering attack, and takes no damage from Magic Missile.

Additionally if the attack is a Critical Hit and exceeds the AC the target takes normal damage instead of double.