"What else can that book of yours do, Ric?" Alex asked, motioning to his now thirteen year-old father, "I mean... this is pretty amazing on it's own... but the things it could do!"
Ric smiled and nodded, he turned to the fridge and began chanting another, inaudible spell that he had memorized. Ric pulled back and said "You should see what we'd be capable of."
Ric looked at Sean as he reached for a box of cookies in the cupboard, watching the thirteen year-old shrink once again. What little muscle definition he had smoothed out, and a bit of baby fat appeared on his stomach. Any hair, besides that on his head, faded away. He got shorter, going from 5'4" to 4'10. Alex looked at his dad, knowing he had to be eight or nine years old now, and seeing that he couldn't reach the cookies. He walked over and lifted his Dad high enough to reach them.
"Ric, he's getting too young now. How can we stop it?" Alex asked.
Ric shook his head and admitted, "We can't. As long as we let it run it's course, the spell will fix him in the end."
Alex instinctively held tighter to his younger father who was finishing putting the cookie jar lid back on before shouting "Ow!" and squirming out of his son's hold of him.
"Sorry," admitted Alex, to the youthened Sean--which seemed almost ridiculous given how Sean was pouting between his chewing.
"Anyway... haven't you noticed anything different?" asked Ric with a smirk that drew Alex from his worries.
Alex turned and focused on Ric. He looked taller and more defined. So did Josh! And then he felt a little wobbly himself as he looked down to see himself stretch slightly.
"What does an accelerated 15 minute puberty sound like to you?" Ric asked grinning maddly.
"You mean... we're growing up?" Alex said, noticing a deeper voice. He covered his mouth in shock as his voice screeched and then settled in a more baritone range. All the while Sean watched, now wide-eyed as he nibbled his cookie.
"Yeah. We are 14 now and Josh is 13." With that, another growth spurt hit. "Sorry. We're 15. Josh is 14.".
Alex looked over his body, it wasn't as clearly defined as Ric or Josh's. Come to think of it, the men on his mother's side of the family were somewhat chunky.
Another round of growing hit. Josh was as tall as Ric now, probably around 5'9". Alex was 5'11". He noticed his pudge was beginning to increase as well... he was probably 180 pounds. But he couldn't think of that as a sudden burst of pleasure and power seemed to surge through him, making the transformation rather pleasureful.
The last growth hit Ric, increasing his height to 5'10". He was a lean, muscular 170 pound eighteen year old. Alex was a soft, round 195 who stood 6'2". Josh grew one more time to 6 feet, 185 pounds of muscle. The three new eighteen year olds laughed at their new bodies.
Sean, finally finished his cookie hopped down from the counter he'd been sitting upon and walked over to his gargantuan son. "Wow! You sure don't get that from MY side of the family." He said, prodding Alex's gut. Then, the prodding stopped. Alex looked down to see his father dwindle a few more years back to around five. On some level the worry that had plagued his mind earlier threatened to resurface only for the feelings of power to smack it back down. So what the pipsqueak might have been his big dad once, and he was just getting smaller and younger--more of an annoying kid brother than anything now. In fact thinking of Sean as his little brother began to feel more natural as memories of his father being older began to grow harder to recall.
"Whatever, little man." Alex said as he picked up his dad from under his arms. "Now, we have important grown up things to do, so you're going to go take a nap." Sean yawned, ignoring Alex, who was now thirteen years older than him, and his patronizing tone. As soon as he was put back down outside of the kitchen, Sean plodded up the stairs, realizing he was quite tired, and found that he had to climb in order to get into his bed. As Sean wrapped himself in his sheets, he curled up in a fetal position and closed his eyes just in time for another shrink spurt as his age dwindled down further and baby fat took over entirely until he was small and newborn.
Just suddenly down in the kitchen Alex felt a little woozy once again as his mind finally cemented thinking of little Sean as his recently born son.