HP/inch 35; Hardness 15; Cost TBD
The metal seems almost alive to the touch. The cool metal seems to almost pulse with life and you almost feel a yearing from it. Or maybe you're projecting your experience from destroying the contruct you salvaged this from. Careful study reveals that it's physical properties adapt to its use.
When wielded offsensively, it appears to grow heavier (+50% weight) and mysteriously leaves a shiny afterimage when swung. As a swift action, the wielder of the weapon can use this afterimage while attacking to confuse the enemy and gain +1 circumatance bonus to AC.
When used defensively, it becomes significantly heavier (+200% weight), able to absorb more shock (+33% AC) at the cost of being harder to wield (+100% Armor Check Penalty).