Shadow Ash

This small pile of ash glows with strange blue embers that coat whatever they touch with a thin layer of frost laced with veins of necrotic ichor. Adding this catalyst to an animate dead spell or Create Undead ritual wreathes the resulting Undead creature in a shroud of frost that pulses with negative energy. During a combat encounter, the first opponent to deal damage to the undead creature with a melee Strike takes 3d6 cold damage and becomes drained 1 as the shroud of ice and rot shatters from the blow. If the undead creature survives the encounter, the shroud of frost reforms the next day. When an undead creature animated or created with this catalyst dies, it can return to animation with half of its Hit Points within 1d4 rounds of its death (unless it was killed in a manner that destroys it remains completely such as a Disintegrate spell) with a DC 11 flat check. If the undead creature rises again, a desperate, garbled screech resonates from within its corpse.