Something wasn't right about this for Jason. Looking at Dad didn't make sense; it was like looking at some fill in actor that was hired to play Dad, but didn't. And John? That didn't sound right...it definitely seemed like things had changed since the morning. As he trudges up the stairs, he suddenly realizes what had changed. Whatever John(?) had in that bag before was what had done this. Whatever this was!
The 10-year-old could hear John's shower running from the hallway. Jason peeks his head in slowly, making sure that he was actually in the shower. He moves into the room, looking around. There were bags on the floor, some shoes, John's clothes from today, and some socks. Jason moves toward the socks, something drawing him to them. In this moment, Jason needs to put them on. He grabs them and pulls them on, the socks fitting him perfectly despite also fitting John perfectly. Even for a 10-year-old, Jason knows something is weird about them. Were him and John the same size foot? That can't be right...his eyes scan the floor for the new shoes again. To ensure that they aren't the same size, Jason grabs them and slips the chuck taylors on, tying them carefully. As he ties the first shoe, they feel much too big, as if his foot only fills half the shoe. When he moves over to the second one, however, they feel a little bit less humongous and more like just 2 or 3 sizes up. Jason stands up, finding the full-body mirror in the corner of John's room. Jason likes the shoes, but they are only the center of his attention for another moment, as his eyes are drawn up to his calf.
"When did I get so hairy on my legs?!" he asks himself, noticing the dark brown hairs growing out of the bottom of his shin and calf. His jaw gapes as the hair continues to grow up his legs, more and more appearing and thickening as he watches in amazement. Suddenly, Jason feels dizzy, gripping his head for a moment until he realizes what is going on. The room around him shrinks slowly, becoming less and less spacious and more confining. The previous 4'10" 10-year-old is quickly approaching 5'5" and still growing. His arms grow hair as well, and his fingers lengthen and toughen as they seem to look more callous and used for manual labor. His arms quickly become covered in thick patches of hair, covering up his forearms which have also thickened. He looks in the mirror as his small shirt becomes ridiculously small.
He panics and yanks it over his head, tossing it to the ground. His shorts feel equally confining as Jason eyes his dick through the fabric of the shorts, which now hugged his muscular legs comically. The shorts and the underwear come off in tandem, leaving him standing there, naked in a pair of Converse Chuck Taylor's, which he now realizes fit perfectly. His quads, now unrestricted, get much beefier, like a football player's or a wrestlers. Jason flexes them and they striate, giving rise to a grin. His eyes rise up to his penis, which is unfamiliarly large. It hangs long and thick, about 7 inches long as it dangles softly between his legs. His eyes continue to rise up to his chest, which is strong and bulky, like a football player in the off season. His biceps are large and more defined, probably 16 or 17 inches around. The measurements come to him easily as time progresses, as though he's taken them recently. Finally, his eyes reach back to his face, which has finished changing. Despite his bulkier body, Jason's face is handsome and chiseled, as well as mature. His hair has receded into his head in some places, getting to a buzz on the sides but remaining long on the top to create an undercut look. Lastly, his face begins to itch. He can see hair start poking out all around his jaw and over his upper lip, creating a stubbly beard that looks like it belongs to a 30 year old man whose had facial hair for years. With that, his body stretches a little bit more, leaving him at about 6'3", and inch taller than his dad.
Where there once stood a 10-year-old pipsqueak now towered a 19-year-old athlete, wearing nothing but a stubbly beard and a pair of Converse Chuck Taylors. In his change, Jason didn't even notice the water stop running behind him, or the door open. As he turns around to find clothes, he is met with the sight of John in a bath towel, standing with his mouth wide open and his eyes directed right toward Jason's dick.
"What. The. Fuck."