Geobukseon Retaliation

Your armor has a retractable spike-covered shell reminiscent of Hwanggot's heavily armored geobukseon, or "turtle ships." The shell unfolds across your body, giving you a +4 circumstance bonus to AC and resistance 2 to bludgeoning, piercing, and slashing damage until the end of your next turn. Spiked chains propelled by small bursts of black powder also erupt from the shell, dealing 3d4 piercing plus 2 persistent fire damage (basic Reflex save against your class DC) to all creatures in a 5-foot emanation.