Adams was walking outside the town when he saw two naked small boys swimming and playing in a small river. He hadn't used the pubertifier since a while and now that Mark had awoken he thought it could be a good time to use it again.
He hid behind a tree and prepared his shot. Shooting both kids at the same time was too risky, so he waited for a opportunity to hit one before hitting the other one.
Almost half an hour later, one the kids went to the forest. Maybe to poop or something else, whatever, but it was the chance he was waiting for.
The boy, probably around 10 or 11 years old was looking at the sky when Adams shot at him. It was painless, so he didn't realize what happened and he kept playing happily, diving into the water.
As he played the pubertification was taking effect but he couldn't see what it was doing to him as he was underwater. He body tingled more than usual, but that was nothing to startle him. He began to age, and right on the edge of puberty like he was, the effects were instantly noticeable. His small childish penis was the first thing to show any sign. It grew a bit, especially his balls, kinky black hair growing in just around it. His legs and arms stretched out, giving him the look of a boy growing taller quicker than his body can keep up. Hair began to darken around his ankles and wrists, his hands and feet also getting awkwardly bigger. A little grew under his arms as he put on a bit of muscle, still looking horribly gangly though. He came out from the water to breathe but he didn't realize what had happened to him, so he kept playing and dove again.
His penis continued to grow, faster now than before, inch after inch it lengthened even as his balls grew in size, only slowing once it neared six inches. His pubes thickened even further, a bush on his crotch rather than the few straggly hairs that had been there before, it even peaked, making the start of a trail to his belly button. The height growth slowed, only to be replaced with sideways as he filled out. His shoulders got broader as lean muscle packed on his growing frame. The hair on his legs and arms continued to darken, moving up his limbs slowly. His face began to change, the child-like features giving way to something more masculine. A few hairs grew in on his chin and upper lip as well as his sideburns. And he felt a slight tingling in his throat as his voice was changing.
He came out from the water and swam to the riverbank. As he was getting closer there, he noted that some things looked smaller than he remembered, where the water used to be at his waist level now was barely above his knees. Shocked by that, he looked down and saw himself, his eyes going wider. "Holy crap...!!" Which surprised him even further, his voice was so deep. He jumped out of the river and looked at his water reflection. He touched his face as he examined himself, still unbelieving. He looked sixteen or seventeen, or at least close to how he remembered his older brother looked at that age. He quickly examined the muscles and hair that had grown all over him before he looked in his reflection again, seeing how his own surprised face slowly broke into a mischievous grin.
Meanwhile, Adams was behind a tree taking pictures of the new man. He was taking a record on a notebook when he heard the other kid coming back, so he began to set his gun for another shot.