"I couldn't tear my eyes from the glow and the longer I stared the worse it got. "The light seemed filled with an evil purpose. It writhed and changed shape as I stared at it, seeming to sweep out through the walls of the cave and back again with a pulsing greediness. "Then, gradually, it ceased to blend with the shadows. It became stationary and transparent, hanging suspended in the murky air like a gigantic burning glass. "As though in a dream-delirium I became slowly aware that a picture was forming within it. A valley swept into view, walled with high, saw-toothed mountain ranges. "Deep in the weaving radiance I could see a tiny, plodding figure coming toward me across the valley. "For an instant I thought I was looking at the far-off image of a human figure plodding over the plain. A figure clad in a heavy space-suit, moving awkwardly--as I had moved. "Nearer it came and nearer, its reflection floating on ahead of it, bobbing about like a little ship. "And then, suddenly, I saw that it was _skimming_ the plain. It was balancing itself on flapping wings, sweeping across the plain without actually touching it, but so slowly that it appeared to be advancing with the plodding, awkward gait of a man. "It swerved abruptly as I stared, made a full turn, and soared into the air. It flew straight toward me, its wings beating the air as though it were struggling against a furious uprush of wind. "There was a sloping wall of light-dappled rock at the edge of the radiance, and for an instant the winged shape disappeared behind it. I didn't see it descend. "I saw only a shadow forming behind the rock, and swirling out from it. It came into view again abruptly, dragging its wings behind it, hobbling toward me over the ice. * * * * * "My spine congealed. The thing that had crossed the valley was a monstrous bird of prey. It was wearing a space-suit, but no helmet, and I could see its vulture-like head bobbing about in the glow. "It seemed to be in pain. It had halted at the edge of the glow, as if fearful of what lay beyond it, and suddenly as I stared it began furiously to pluck and tear at its breast with its taloned foreclaws. "So frenzied were the creature's exertions that the front of its space-suit came away in shreds. The hideous creature had scales on its breast instead of feathers, and a pulsing, lizardlike throat ... a throat which turned red as it continued to inflict cruel injuries on itself. "The impression I got was one of agonized despair, of a creature trapped and cornered that could only escape by destroying itself. Again and again it slashed at its flesh, twisting about in the glow, its eyes brimming with agony. "Then, suddenly, it was no longer alone. A little bird-lizard shape had materialized at its side and was going through the same grisly pantomime.