... her belly ripples and begins to grow larger... much larger than it was beforehand!
"Oh! My goodness!", she exclaimed, arching her back as her stomach surged forward once more,rapidly attaining the size of first a nine-month pregnancy... then a nine month pregnancy with twins... then quadruplets... and then to the size of an average beach ball! And still it continued to grow beyond that before Mary's marvelling gaze. Her breasts, already engorged with new milk from the effects of the prior potion, did not grow much larger than they were already, but they were still hitched upwards due to the swelling mass of her one-again growing tummy below them. Remarkably, although Mary's size and her center of gravity both shifted remarkably within the span of just a few moments, she did not lose her balance or wind up forced to the floor by what *should* have been the weight of her growing belly... Perhaps the atypical nature of the transformation vials meant that their effects would always be something that their drinker could physically handle? Whatever the case may be, Mary wobbld as her balance shifted, but neither fell over nor found the mass of her new belly too much to bear. Soon, her belly had expanded to the size of a bean-bag chair, and the edge of its front side now reached just over two feet away from her body.
Mary's eyes widened as she took in her new form. "Oh wow... I... I'm so biiiiig...", she said, wonderingly, and she rubbed her hands over her expansive belly. It was then, that the flesh of her tummy rippled under her palm, and she gasped felt a powerful motion from the huge infant that she now carried within her. It happened again, and, before Mary's astonished eyes, she saw the faint outline of a hoof press against the surface of her belly, followed quickly by the brief glimpse of the outline of an equine snout before it rolled off and away to the side of her tummy.
"Ohhhh...! It *DID* change my baby into a horse foal!", Mary marveled, excitedly, clasping her hands over her chest. Despite the fact that the child she carried was no longer human, she found the idea that she was now carrying an unborn foal within her body to not bother or upset her one bit. She *did* love horses after all, and she had drank the horse potion in the first place with full knowledge that this might potentially be an outcome. She wondered if perhaps the potions might somehow be sensitive to the wishes and intentions of those who drank them, and that tat might be why her unborn child became a foal, rather than herself trning into a mare, or some other outcome. Regardless of the reasons why, she was very pleased. She was carrying an adorable little foal now! She was making a living horse within her womb! She giggled happily and continued to feel the strong motions of her huge equine child as it tossed and turned within her...