"Mary!" he shouted again, but this time his voice sounded deeper, more guttural and booming. It was enough to make her check her approach to her death strike for a moment and then to scuttle backwards as the cocoon he was bound in began to quake and shudder.
Jeff felt a painful build up of pressure and he cried out, in that same booming voice. Through the thick webbing the first couple of his enormous, thickly jointed spider legs erupted wear a noisy tearing, possibly the webbing, possibly skin and bone, possibly both. "Mary! It's happening! It's happening to me!" he exclaimed as several other drider legs broke through.
The female drider's many eyes opened in excitement and she hissed her appreciation. "Yeesssss! Oh yes my love! Become my worthy mate!"
The cocoon had now lost most of its integrity and he rose from it, unsteadily but rapidly strengthening onto his with legs as a large, shiny spider's abdomen bloated from what had once been his backside and hips. Where Mary's skin had turned a silvery white, Jeff's was rapidly darkening, even while his muscles corded beneath that skin and his bulk increased.
He gurgled with pleasure at his changes, having not even noticed that sensation had replaced the initial pain. He was easily as large as his mate now, and was still growing, his abdomen more oval shaped than that of Mary, jet black with a splash of red colour where it pointed to a tip. As he looked at her, his vision brightened into what seemed like a high definition version, as his extra glossy, pupilless black, blank eyes opened across his forehead.
That forehead was much larger than before and his hair was quickly falling out, coming away in great handfuls as his nails sharpened into long, polished black claws.
"THIS! IS! WONDERFUL!" He boomed. "SUCH STRENGTH! SUCH POWER!" His skin was a deep grey-black now and with a final grunting of effort his hairless head erupted into a cresting crown of bone, splaying upwards and backwards above his pointed ears.
Mary approached him once more, smaller than he, although not completely dwarfed by his impressive presence. "My love, my King!" she rasped with arousal, her monstrous cunt beginning to run with a slimy fluid of drider woman's wetness.
"MY QUEEN." He replied, his black lips parting to show his sharp teeth and long tongue as he spoke. "YOU HAVE GIVEN ME A GREAT GIFT. NOW, I SHALL RETURN THE FAVOUR."
Where his human torso met his drider abdomen a large, long, sheathed cock extended from his body, as dark skinned as the rest of him, covered in a glistening slick, it sported many barbs down its length and under the egg-shaped knobhead that already dribbled a thick pre-spunk.
Instinctively the two drider grappled with each other with their gigantic legs to come together and Jeff pushed his inhuman penis into Mary's perverted womanhood. The pleasure was incredible, greater than he had ever known as he plunged his cock deep, the barbs transmitting every teasing ridge of her deep, suppurating cunt's texture into his brain, flooding his body with ecstasy. One purpose of the barbs at her entry now became apparent as she used them to feed his length inside her.
They locked their lips together, tentacle tongues slithering around each other. Her large milking teats which crowned her swollen tits leaked as they mated, the more his barbs stroked her, the greater her drider body responded in its obscene ways. When he came, the explosion made the two of them screech in passion, a horrific, deafening mating cry as his gigantic internalised gonads hosed her belly with thick, meaty, hot drider semen. She thrashed in his grip, hissing and rasping in wild pleasure as her own orgasm tire through her body, squirting her vile slime over his vomiting cock.
Afrer they had disengaged from their unholy union, Mary ran her clawed hand over the bulge of her belly. "You have filled my womb my King" she rasped. "What usss your wissshhh now?"