Terror-Forming [two-actions] Feat 14

Your weapon blasts apart the battlefield and leaves it a ruinous waste. You Area Fire or Auto-Fire. You don’t designate a primary target, but instead make each square in the area of your attack difficult terrain. If a square was already difficult terrain, it becomes greater difficult terrain. Any difficult or greater difficult terrain created by this action remains in place and can’t be changed without extensive engineering or magic.