The thing floated smoothly above one of the smoking chimneys, flattening itself to bathe in the searing updraft of unthinkable pressure and heat. Hot bubbles seethed beneath it, sliding with frictionless ease off its mirrored undersurface. As they watched, it drew itself together into a rippling globe. Then, liquescing with sudden speed, it poured itself through a thumb-sized crevice into the core of the heat vent. It vanished at once.