The Black Heart dwarves, or Duergar slammed their dark colored hammers down on the black mithral, some of it stretching out a bit before finally finding shape. The stretch metal forges were freezing coolers, and on the other side regular forges, for the fact they needed to heat of the metal, and then freeze it quickly to make it last long enough to be able to make shapes. The normal metals were only heated, because they would never be able to turn into a rubber like material. One of the dwarved looked up from his work, to see a kobold standing over it. He frowned at him in anger, "Leave me be, ye dragon born dolt, or I'll kill ye" he said simply, waving his hammer a bit to make him move. He looked back down, slamming the brick of cold stretch steel as it boucned down and lay flat.