Jenny falls to the ground as the stomach ache continues. It quickly spreads through the rest of her body as she crawls into a fetus position.
Billy laughs at first, but soon a worried looks flashes across his face. "Jenny, are you alright?" he asks as he walks up to her. As he comes closer he hears how she's drawing short, raspy breaths and is shaking violently. "Jenny?"
Before Billy can say anything more he gasps as he notices how tight Jenny's skirt has become. Her entire body is swelling and soon the seams begin to burst at the ends. Jenny rolls over and Billy can see how her previously flat chest begins to expand and soon burst through the thin cloth.
Had Billy been a few years older, the sight would probably have made him at least really horny, but right now he's too scared to even do anything but stare at Jenny who is slowly turning into a full-grown, and very stunning, young woman.
Finally the changes are complete and Jenny stops shaking. Her now C-cup breasts jiggle a bit as she continues to draw her sharps breaths. Nipples much longer and harder than mere minutes ago have grown dark-red as blood pulse into them. Slowly but surely Jenny gets up and looks at Billy.
"B-Billyyyy..." she murmurs, getting up from the ground. Billy takes a few steps back, growing pale. He remains frozen as Jenny walks over to him and take his super-soaker from him. "I'm just going to borrow this," she say with a deep, sensual voice. She swaggers over to a garden-hose and begins to fill the tanks slowly. As she's done she put the hose in her mouth and drinks heavily from it. She doesn't even notice the small lizard that's bitten her (quite understandable as she stepped on its tail).
She turns back to Billy and aims the super-soaker at him. "Time for some more fun, Billy." She say with a big grin. She fires a stream of water at him and he's struck in the chest, soaking him completely. At first nothing seems to happen, but suddenly Billy feel the same stomach-ache that Jenny felt shortly before. He gasps as he see how his hands begin to swell...