It was stamping down upon him, shaking its bridled head, snorting, lifting its lip above the impossible teeth. He saw the reins hanging loose, he saw the saddle and the swinging stirrups. He knew that the only safety in this hall for him was paradoxically upon the nightmare's back, where the hoofs and fangs could not reach him. But the terror and revulsion which the boy had buried long ago came welling up from founts deep-buried in the man's subconscious mind.... * * * * * Now it was rushing him, head like a snake's outthrust, hissing like a snake, reins flying like Medusa-locks as it stretched to seize him. For one instant he stood there paralyzed. He had faced dangers on many worlds to which this nightmare was nothing, but he had never since boyhood felt the paralysis of horror that gripped him now. It was a child's horror, resurrected from the caves of sleep to ruin him.... With a superhuman effort he broke that frozen fear, snatching for the flying reins, whirling as the monstrous thing swept past him in a thunder of terrifying hoofs. Desperately he clung to the reins, and as the thing rushed by he somehow got a clutching hand upon the saddle-horn and found a stirrup that swung sickeningly when it took his weight. Then he was in the saddle, dizzy still with the terrors of childhood, but astride the nightmare. And now, with a sudden intoxicating clarity, the fear fell from his mind. For an instant he sat high on the back of the incredible fanged thing, an old, old terror clearing from his mind. Confidence which was, he knew, his own and no bodiless reassurance drawn from dreams, such as he had felt in the jungle, flooded warmly through him. He was not afraid any more--he would never be afraid. The festering terror buried deep in his childhood had come to light at last and was wiped away. He caught the reins tight and flashed a sudden grin around the hall-- Brazen laughter boomed through the building. And beneath his knees Stuart felt the horse's body alter incredibly. One moment he was gripping a solid, warm-fleshed, hairy thing whose body had a familiar pitch and motion beneath the saddle. Then, then-- Indescribably the body _writhed_ under him. The warm hairy flesh flowed and changed. Cold struck through leatheroid against his thighs, and it was a smooth, pouring cold of many alien muscles working powerfully together in a way no mammal knows. He looked down. He was riding a monstrous snake that twisted its head to look at him in the moment he realized what had happened. Its great diamond-shaped head towered high and came looping down toward him, wide-mouthed, tongue like a flame flickering.... It laid its cold, smooth cheek against his with a hideous caressing motion, sliding around his neck, sliding down his arm and side, laying a loop of cold, scaly strength around him and pressing, pressing....