at will, you create an aura of energy that prevents you from taking damage and grants you a +4 to your AC until it dissipates. it dissipates when you are hit with an attack or would take damage, however said attack deals no damage, once the barrier dissipates every creature within 10 feet of you must make a con/dex save with a dc of (10+ your con modifier), if they fail, they take (1d12+ your proficiency modifier) force damage and they must make a cons save with a dc of (10+ your str modifier), if they fail, they are knocked prone