Will was starting to feel oddly hot when he got to his room - literally, he was feeling what felt like the entire heat of a furnace, concentrated upon him, yet it burned in equal measure to feeling somehow so incredible he could only let out a series of groans and grunts as he fell on to his bed. He was a mess of sweat as he writhed and twisted upon his sheets, his body was undergoing a startling metamorphosis...
The cabin had seen his earnest desires - and decided to grant them...at a steep price. It had seen just how deeply Will desired to run alongside his brother and surpass him handily, yet he was held back by the stark betrayal of his young body and how it seemed to lack development. And now, as Will turned and grit his teeth, testosterone boomed throughout his body - his mouth letting out several more grunts and groans as he progressed well beyond the age of eighteen;
Owing to his lack of development, the Cabin went into overdrive developing Will's body.
His arms pumped as he gripped the sheets, biceps and triceps swelling and surging with sheer size, veins rippling through as his biceps took on the gruff size of twenty inches, exactly as Will wanted, the swoop of his tricep nicely complimenting his bicep. His forearms and hands grew strong and thick, the veins shooting through, prominent. The muscles in his shoulders were next, swelling with size and strength - enough to handily rip his shirt asunder at the shoulders, strikingly huge at the front, lateral and rear. His back swelled with width and his lats surged to match them, spreading his stance.
Will's jawline seemed to respond to being grit so tight by strengthening and broadening, giving him a devastatingly handsome, masculine visage. Anyone who saw Will now would see a handsome, bushy haired male model covered in sweat that accentuated his growing, bulging pectorals which ripped holes in his shirt, and he outright screamed as his abs defined themselves, both screaming in pain and in pleasure both - his groin feeling the shot of testosterone from swelling testes.
His cock grew from barely four inches to a lover-satisfying nine inch monster of a dick, which slid down his pants leg as it hardened, held between his growing thighs and quads, which were growing thicker by the moment, his muscled ass lifting off of the bed as he madly humped at the air. He didn't know WHAT was going on, he just know it felt amazing and also hurt in equal measures. Last to grow were his calves, which swelled into diamond like configurations - every inch of him was much bigger than he ever thought he could be prior.
At age 20 the heat started to abate, and Will was able to become coherent again, laying there basically in a puddle of his own sweat.
"What...what the fuck was that...?" He didn't care about familial rules, he cared about the fact he felt like he almost got baked alive by whatever that was.
But as he stood up and walked uneasily on strong legs into the bathroom, he was shocked by what he saw. A version of himself he had fantasized night and day about, but whom he thought would remain fantasy. He put up his arms into a double bicep flex, "I-I'm...I'm strong! I'm big! I am...I AM HOT!"
Will enjoyed the thickness of his muscles, the strength of his development, and just as he did another flex, he winced and shook his head, "Yeah oww, what the hell was that?" The feeling was less intense than last time because less intensive alterations needed to be made.
Age 21, Will watched as his face grew a slowly thicker coat of five o'clock shadow stubble, shoulders widening just a little more...
Age 22, Will realized upon seeing the treasure trail which was modest just a moment ago grow thicker and then suddenly buzz back down it was not done yet. He realized with a gasp...
Age 23, "I'm getting older. It's...it's not stopping," he said, taking a step back away from the mirror. His manhood was still thick, still aroused from the sheer thrill of this and now the shock from what he realized about himself, "Dammit...this. This is GOOD! Make it STOP!"
Age 24, Will was starting to both get worried and realize his cock was still not calming down. He had to find a way to get this to stop before it went too far! But at the same time... Will grunted and pawed at the prominent bulge...maturity...or indulgence?