Of course Jim really wanted to give the machine a proper field test. Who wouldn't want to see just how much he could change? And of course, he'd already tried some actions on himself. But then, that 'modify' option was extremely tempting. With Carol sitting right there, what kind of brother would he be if he didn't cause a bit of mischief. Promptly, Jim typed the command, careful to include some specifications so that he could fully watch the magic happen.
>MODIFY CAROL BECOMES MALE. ONE MINUTE TRANSFORM. AWARE OF CHANGES. DOES NOT LEAVE HER SEAT
After sending the machine to do it's work, Jim quietly approached his hiding spot behind the wall. Not that he really cared what his sister did to make her extra cash but the girl was out of control. He cared about his sister...pretty much. Maybe this would get her to take a break and actually do something respectable for a change.
What Jim hadn't noticed were the internal changes happening to Carol as he continued thinking to himself. Carol didn't either, fully involved in her TV show. Not until the more noticeable changes began to occur. At first, her torso started lengthening. Her t-shirt started rising off her hips and soon left a gap of skin exposed, showing off her toned abs. Men in Jim and Carol's family had always been on the taller side. She must not have felt much because soon her arms were getting longer and soon her legs were following. It wasn't until she felt a slight tingling in her chest that Carol noticed her breasts quickly deflating. The implants were long gone and her natural B-cups were following suit.
"Holy shit! What the hell?" Carol shrieked, moving the bowl of popcorn from her lap as to not throw it away in concern. She reached up, touching the now firm pectoral muscles underneath her ridiculously empty bra. Her toned build was transferring from her original state. Yet, as concerned as she was, Carol didn't get up, nor did she feel compelled to. She was just being forced to watch her transformation from her seat.
Her arms thickened, biceps bulging outwards to create firm curved muscle. Her legs and chest followed suit. In her current state of limbo, she looked like a very neutral gender or at least a jacked female. Although, that wouldn't last for long. Her dark brown hair started retracting back into her scalp. Feeling her long locks moving up her arms, Carol held up her phone in camera selfie mode to see her pouty lips thinning, her delicate female jaw squaring up, and even an Adam's Apple becoming way more prominent on her thin neck. Her neck thickened, her face filled and changed fully to a 21 year old boy. Very reminiscent of Carol.
Jim watched, amazed as the extra mass appeared on her sister, now leaving an admittedly attractive young man on the couch in a t-shirt that was too small and sweatpants that were extremely short on him. Jim had really turned Carol into a male...Well, except one bit. Both siblings had just been waiting for that. Although, one more than the other. Carol felt her clitoris starting to swell. She was far from aroused and way more panicked but she could feel it growing rapidly. Soon it was rubbing against the fabric of her panties making her loud new voice work with a sudden, "no, fuck, no." She was so surprised by the sudden baritone but even more surprised when her panties began feeling uncomfortably tight. Pulling her panties and pants down, Jim was in awe. First of all, he had to fight to look away. But then definitely couldn't miss the small, slick nub starting to poke forward out of Carol's thighs.
The clitoris took on a tubular form, bearing no semblance to it's original form but now definitely penile in shape. Soon, foreskin began appearing around the expanding tube as it went from an extremely hardened state to a soft 5-inch phallus that plopped on her thighs. Testicles and a scrotum had been inflating rapidly between Carol's legs unbeknownst to her. She had been way too shocked at the erected penis that had been staring up at her just moments before.