The ruby dragoness's clawed hand held one each of the three candy colors: red, blue, and black.
Mary still couldn't be completely sure on what each candy did, with her only hints being the picture on the bottle and the transformations so far. Given the femininity of the label's red dragon and that of her parents, one of whom had previously been a man, the red gummies likely turned people only into female dragons. Mary's own transformation via a black candy retained her sex but gave her a second pair of breasts, and she hadn't become as vibrantly feminine as either of her parents. Nobody had eaten a blue candy yet, but the nearly-absurd musculature and lack of femininity on the label's blue dragon implied a masculine dragon transformation. More importantly, however, nobody had eaten more than one color of gummy at once yet, let alone all three at once.
While part of Mary felt sorry for what her brother was experiencing, she was filled with anticipation more than anything: both to see what exactly would happen from the multiple candy colors interacting, and exactly what kind of sexy beast her brother was about to become. It didn't occur to her to wonder why she was thinking of her brother's future dragon form as sexy - which is just as well, since she'd already been thinking that about her parents for a good while already.
Meanwhile, Mark was still being held by the amber dragoness, apparently his mother, while the ruby one who claimed to be his father was offering him dragon-shaped gummy candy from her clawed hand. Despite the absurdity of the situation, Mark was having a hard time being as scared or suspicious as one would expect him to be. He looked to the dark-red dragon, who could only be his sister, Mary. Maybe it was just him, but she looked almost... excited.
"They are really tasty," Mary found herself saying.
Knowing that he wasn't getting any more help than that, Mark slumped in his mother's arms, before weakly taking the candies from his father's claws. "I'll take your word for it then," he said as he began to eat them. As he did, his mother released him from her grasp, and both parents carefully backed away as Mark was enveloped in a flame, obscuring him from sight. Only seconds later, though, the flame disappeared and Mary could see her brother clearly again. Had her own transformation been so fast? Thinking about it, her parents' changes probably had been, considering how little time had passed between her leaving the candy bottle behind and her parents' roaring. Curious how such drastic transformations could happen within seconds.
Now that Mark was visible again, though, Mary wasn't sure "brother" was quite as appropriate. Mark's frame was larger overall than before, especially with that sizeable musculature beneath her dark violet scales, but her figure was more androgynous, having distinct curves without being overtly feminine. Those grapefruit-sized mounds on her chest, on the other hand, were pretty overtly feminine, though they looked smaller against her toned frame and still somewhat-broad shoulders. Mark did still have a penis, if that bright violet spiked shaft at her crotch was any indication, but a closer look at her genital slit revealed a violet snatch that was slowly leaking lubricant down her thighs.
Mary could understand the combination of masculine blue and feminine red candies reacting to turn her brother into an androgynous hermaphroditic dragon. The fact that Mark now had two identical draconic heads on her shoulders, however, was probably the work of the mysterious black gummy. Despite such a radical change to her already-different body, Mark didn't look disoriented as much as confused, trying to process her myriad transformations. Mary watched as her older brother began to slowly prod and caress her new breasts, rub at her spined dragon dick, and even tentatively bring a finger to her vaginal entrance, all while her two heads moaned and roared in unison. The other dragons watched with interest as Mark quickly worked herself to orgasm, her muscles visibly tensing, her tail curling inward, her heads trying to kiss one another but not quite having enough room to face each other directly.
Robert and Melissa, not bothering to conceal their own smoldering lust, sauntered over to where Mark lay panting on the floor. "Are you feeling okay, sweetie?" Melissa asked, kneeling to meet her son's faces.
It took Mark a few seconds to respond. Her heads looked at each other, still panting, and grinned. "Really weird," said her right head. "Super weird," her left head continued, as she continued to caress her breasts and genitals. "But I think I can get used to this."
"Kid, as loud as you were, I'm surprised that Jenny still hasn't heard us, even through those headphones of hers," Robert chuckled as she sat next to Mark, pulling her close and grabbing Mark's breast in the process. "I swear, she's gonna blow her ears out."
Melissa bent down and brought her face to Mark's soft penis and scaly cunt. "Dear, don't be too hard on her. Maybe we can teach her how to blow other parts of the body," she said, taking Mark's cock in her maw and beginning to lick it.
As the amber and ruby dragons began to tease the still-sensitive amethyst dragon, Mary could no longer resist the urge to relieve her still-unsated lust. Wiggling her hips and tail suggestively, she strutted over to join the rest of the dragon family. In the back of her mind, she wondered if, or when, her little sister would ever join them.