Jeff looked out his window and saw the perfect targets. His brother Nate and his friend Noah were outside, play-wrestling each other. Both were 13 and pretty skinny. Any addition to their muscles would be immediately apparent.
Jeff chose to hit Nate first. He set the machine to change him from a 28 to a 58. Then he fired it.
Down on the ground outside, Nate had been pinned down by Noah when suddenly he felt a surge of strength. He hooked on and soon his friend was the one laying pinned to the ground.
"Jeez man, when did you get so strong?" Noah panted.
"I don't know, it just happened," Nate explained. He wasn't even breathing hard.
"Um, dude?" Noah said as he stared at Nate, his eyes wide. "You're growing."
"Huh?" Sure enough, when Nate looked down at himself, he could see how tight his clothes had grown. His shirt began to hike up, exposing his new six-pack and barely covering his swelling pecs. It was practically cutting off the circulation in his tight biceps. Even his legs were getting squeezed by his jeans as his thighs and calves swelled.
Now Nate's shirt exploded, revealing his barrel chest and thicker neck and arms. His jeans began to tear in certain places until soon they shredded entirely, exposing his legs like Greek pillars.
Nate was embarassed to be caught in his boxers, but Noah didn't seem to care about that.
"Dude! Look at you! You're huge! You're probably the biggest kid our age I've ever seen! " exclaimed Noah excitedly.
Nate began to examine himself, flexing an arm, bouncing his pecs.
Jeff thought maybe he should alter reality, so he did. Checking Nate's room, he found a lot of weights and things, along with mementos from a childhood of bodybuilding, while playing sports on the side.
Jeff loomed back outside. Nate was clothed again, but this time in a tank top and shorts. Neither he nor Noah seemed to notice it anymore.