Melissa fell to her hands and knees and clutched her stomach as an alien shifting sensation in her belly overwhelmed her. She groaned as she felt her insides migrating downwards. She rolls onto her side from the bizarre feeling, and curls into a fetal position. Feelings of fear and disgust fill her as the sensation nears her groin. When she feels as if it can descend no further, it somehow does exactly that, and she suddenly begins to feel an odd lump between her legs. Confused, Melissa rolls onto her back and spreads her legs to inspect her crotch and practically faints at what she finds.
A tiny cock has sprouted up from what used to be her clit, with a pair of small testicles resting beneath it, and furthermore, the space beneath it where her vagina used to be is utterly bare! She touches her cock gingerly, and it suddenly springs to life. It begins to grow in length and girth, quickly sprouting from a mere half inch long to a 12 inch monster cock that is as thick as a can of soda, the skin covering it losing its feminine softness. Her testicles swell to the size of tennis balls while the sack containing them can now droop halfway down her thighs. Melissa is stunned at the sudden changes to her genitalia, but her swollen balls quickly start to producing inhuman amounts of semen, flooding her with male hormones and thus leaving her only able to think of one thing.
Barely thinking, she grips her monster cock with both hands and begins to pump it furiously. The pleasure that she is rewarded with is immense, but it isn't enough. She HAS to release the pressure in her balls, she HAS to cum right now! Her whole body grows from 5'8 to 6'8. Her slender arms rapidly gain muscle mass while her delicate hands around her cock grow large and rough to match her new bodybuilder arms. Her smooth, feminine legs and feet follow suit, becoming thick and hard with muscle.
Her cute B-cup breasts recede, and are suddenly replaced with massive pectoral muscles even bigger than the boobs that were there before them. Her shoulders grow broad, her hips grow narrow, and her ribcage expands, making her chest seem even larger. Her cute, curvy midsection suddenly grows wide and toned: her flat tummy sprouting an impressive six pack and her gentle curves widening and hardening into an unmistakably masculine figure. Finally, her beautiful face is morphed into something new: her eyebrows become thick and bushy, her pouty lips grow thin, her jawline grows strong and angular, her nose grows larger and prominent, and her long black hair retreats into her scalp until nothing is left but a dark buzz cut. A dark, coarse patch of hair begins to sprout up at her crotch, covering her scrotum and the base of her cock. The hair then spreads all the way down her previously smooth legs and leaves a thick blanket of hair atop her feet. It then spreads all over her chest and torso, covers her armpits, spreads down her arms to her hands, and finally, creeps up further and leaves a nice layer of stubble across her newly masculine jaw with sideburns all the way up to her hairline.
Melissa feels her orgasm drawing near and lets out a booming moan in her new baritone voice. The new man screams in ecstacy, massive amounts of cum spewing forth from his newly formed and impressive manhood, coating himself, the room, and the other new man laying a few feet away. Melissa is finally able to collect his/her thoughts, and begins to assess the situation. However his cock is still begging for attention, and while his urges are manageable for now, they are growing stronger steadily. Melissa, formerly and attractive schoolgirl, is now a 6'8 tower of pure masculinity complete with a foot long monster cock and incredible muscles, just like the other girl before him. It suddenly occurs to him that he isn't alone in the room. He turns to face the still masturbating man behind him, when his monstrous cock suddenly springs to life again. While he starts to again tug frantically on his member, another situation develops with the girls that ran outside...