As Mary’s eyes were fixated on the massive and still growing form of Jim’s father, her boyfriend was starting to complete his own transformation rather quickly. Gasping in horror, Jim watched, as he was completely overtaken in smooth blue scales just like Mary as he reached an impressive nine feet tall and his clothing began to tear. His breasts, which were substantial and firm, accentuated his now perfectly feminine curves. His long tail curled around his right leg and his long neck stretched to a nice long four feet while his head had reshaped to a Brachiosaurus just like the others. Now a stunningly sexy and pleasingly full-figured anthro Brachiosaurus female, Jim’s changes slowed and then stopped entirely. He could only gape at himself helplessly; not entirely dissatisfied with his plump curves and deliciously large breasts, but certainly upset he had become a large female dinosaur.
Excitedly, Mary turned back to Jim’s mom. She was in a state of blissful arousal, vigorously masturbating her new and increasingly large penis through the tearing fabric of her strained dress. Being ten feet tall, the ex-woman’s musculature had become amazing. Every inch of her flexed with firm bulging muscle, her pecs and abs swollen and stretched tight, her thighs massive, legs and arms rippling with muscle as she jerked her penis. Her penis! Mary had seen an erect horse once on her uncle’s farm, but the member this giant Brachiosaurus possessed put a horse to shame. The huge rod reached up to the creature’s chest and was thick and swollen with the head mushroomed obscenely. This was to say nothing of her large basketball sized testicles, which hung over the edge of her chair and pulsated with her dick. Her neck continued to stretch, and she continued to grow larger, showing no signs of stopping anytime soon.
Jim’s dad was truly massive. Mary began to get worried as she looked to the other transformee and saw a confused looking and still growing giant dinosaur begin to fill the room up. He had fully lost his anthro state, now standing on all fours. His arms, or rather, his front legs, now sported the same elephantine feet his back legs possessed. As he had been growing all this time, he had taken on a less and less human shape. Now, his front legs were much longer than the back, and his muscular torso had shifted and resculpted into its proper quadropedal stance, his spine forcing him down on all fours. His chest and torso lacked any human definition and had barreled out and inflated sufficiently to support his bulk. He was still clearly muscular though, as his big meaty thighs and legs showed strong definition. What Mary couldn’t believe was how large he was now. His body was now 14 feet long, his five-foot tail raised off the floor slightly. He had grown to nearly twenty feet in height, most of which made up by his long flexible neck, which was so long his head was brushing the other end of the room, past Jim. His expression looked dumbfounded. Mary couldn’t help but glance between the giant dinosaur’s legs to see the large dangling balls and positively enormous genital sheath. What Mary realized was that Jim’s dad wasn’t even half the full size of an adult Brachiosaurus, and if he had dosed himself completely, as seemed to be the indication, he would be a lot bigger quite quickly.
Mary herself was now the least developed of the four of them. Although she herself had been changing all this time as well, her small dosage of the Brachiosaurus vial ensured it was happening slowly. She was only eight feet tall, and while her clothes were starting to rip and strain her body, her neck was only two feet long and her tiny nub of a tail was just a little over one foot. Her smooth blue scales were completely grown in, though, and her flat-toothed jaws were only just starting to push out into a snout.
Enjoying the show, but concerned her house might get wrecked, Mary decided she should shrink Jim’s father. He was presently too big to get out of the room anyway.