Entropy Shield

You wrap yourself in an unknown invisible energy that extends 2 feet out from you. This energy protects you from attacks. When you are subject to a melee or ranged attack, it has a 50% chance to not hit. You roll this percentile die after you know the attack roll. This affects natural 20’s as well. 

Additionally, you repel extraplanar creatures. Any creature not from your plane of existence with a CR of 1 or lower flees when within 60 ft of you.