"Aaaahh!!!" Mark screamed as the light covered his body.
"Is it painful?" Adams questioned. "I thought we wouldn't harm the boys."
"Don't worry. Normally, the gun don't use to be painful." The lady scientist smiled. "But I like it this way. It's more... arousing."
Adams blushed after thinking about that.
"Anyway." The lady continued. "If you need to know, this red button can induce a heat energy on the target. Very useful if a kid becomes aggressive and tries to hurt you."
"You talk as if they were animals." Adams replied.
"Men are animals." She said. "The manlier the boy gets, the more animal he becomes."
Adam blushed again. This time even more.
"Look." She said. "How does a kid look? Small, weak, tiny penis and barely hairy."
Adam looked at Mark and realized he was already changing.
"Look. It just took a few second to make him taller." The lady told him. "He has grown over 1 ft! And talking about feet... look how big they're getting. What size are you?"
"M-me?" Adams stammered. "12."
"I can see that." She replied. "Nice cute feet you have! Very manly!" He blushed again. "This kid could share shoes with you if he keeps growing. Look!" She looked at Mark's feet again. "He's growing hair on there! Do you have hairy feet too?" She grinned. "Of course you have! I like men with big hairy feet like those!"
"I-I don't know what to say..." Adams' blusing was becoming usual. "I'm not a very seductive guy... there are other more attractive..."
"I can see that." She sighed. "Some of these boys could turn manlier than you, but you're kind of... cute."
"The subject has reached his higher levels of testosterone." A scientist near a computer said.
"Excellent. We can already see its effect on the subject." She replied. "Increasing muscle mass."
Mark's chest was pumping up as if he was filling with water. Two solid pecs blew out at the same time his back broadened along with his shoulders which grew wide and manly.
While Adams looked how Mark's nipples moved downward in the perfectly solid pecs, he also noted how his abs were emerging in his abdomen one by one until they were a well-defined six pack.
On the other hand, his arms were pumping continuously as they elongated. The same muscle mass filling was going through there, growing his biceps to bowling ball proportions. Mark flexed them unconsciously as they inflated. When the energy moved through his wrists he felt how his hands grew as well as his toes get meatier and meatier.
"Adams. Pay special attention under his waist." The lady scientist said. "Our last research was focused on improving that area."
Adams noted how Mark's legs were pumping in a similar way that his arms did. They grew and grew until they were as thick and heavy as tree trunks. His already big feet became even bigger and meatier to put Adams' feet on shame.
"It's amazing! I can believe how that boy who used to be way too smaller than me is now way more... bigger!" Adams shouted astonished. "He got the body of a dream life in just seconds!"
"Yes." The lady scientist smiled. "But muscles aren't the only thing that men have."
"Aaaaaahh!!" Mark screamed, now in a deep and rich baritore thanks to the adam's apple that grew along with his new thick neck. "Pleaase..."
"Isn't over yet?" Adams asked to his superior a little worried for the guy.
"Of course not." She replied. "Are men hairless? No! A lot of testosterone means a lot of bosy hair too!"
At the time, hair began to sprout from everywhere on Mark. His former hairless arms and legs get a remarkable amount of hair. His neck and jaw grew a subtle stubble which quickly thickened to become a solid beard, not so big but more dense than on a regular man. Alongside with it, his chest and abdomen grew a thick forest of hair that completely covered Mark's new pecs and six pack. It was so thick that when it reached down the waist it sprouted into a jungle so wild that it bulked the rope that still tried to hide what was left from Mark's boyhood.
"You can take that robe off, Adams." The lady said. "We didn't need to cover his modesty anymore. He is no longer a child."
Adam approached Mark and put his hand on the former boy's waist. He realized in that moment how different his skin was, it wasn't soft like before, it was tough like stone now. He sank his hands in Mark's bushy pubes and took off the robe.
He didn't believe what he saw. Mark's penis was still the small and innocent one from a boy. But it didn't last too long. The first change he saw was on the testicles, they went from raisins to chicken eggs in seconds! And they really looked like two chicken eggs! Confined on a now cramped scrotum which began to elongate like bubble gum until it hung very low his thighs.
With that increased semen factory down and the messy bush above it. Mark's childish penis looked pathetic. He knew it was the last of himself who was left on him. He was still on pain, but also he was ashamed of what had happened to him. When he felt that the pain turned into an uncontrollable arousal concentrated in his genitals, he knew that he must use his last effort to don't succumb to the urge to jack off. He tried whit all that was left of his will but he felt how the blood was pumping his dick like never before.
The puny dick began to grow and grow. Longer and thicker at the same time. From a baby pinky to a soda can and then to a fat salami. The foreskin which Mark didn't know until then had grown back stretched as long as it can until it moved back revealing a big, pink and glowing mushroom shape that was pointing to the sky.
"I can't hold it..." Mark moaned as he fought the need to touch his new manhood. "Pl-please!" It was his final word when, even without thouching it, his mammoth dick erupted all the excess of testosterone in his body. Cum splattered everywhere even Adams body and clothes. After a long session, Mark finally fainted and fell on the floor exhausted.
"It was so intense!" Adams said as he tried to clean his face.
"That amount of semen is normal if we take acount of how many years of sexual activity we have accelerated on his body." The woman said. "I have to take some notes about the testing. Can you take care of him meanwhile?" She asked Adams. "Guards!! Take the erm... boy to the cabin."
The guards took Mark on their shoulder. He was really heavy now! And took him out the laboratory. Adams followed them a few steps behind but he was stopped a second by the woman.
"Ah! I forgot!" She said. "Take the pubertifier. You can run some more tests while you're in the cabin."