Bethany giggled. “Well we need to make you grow of course.”

Amanda smiled and handed the gun to Bethany. “I thought you’d never ask!”

Amanda stood back and closed her eyes, picturing the Amazon she was about to become. Bethany didn’t bother to look at the dials that Amanda had twisted and simply fired the gun at Amanda. The yellow beam shot out, but seemed a bit more intense than it had before.

Amanda opened her eyes and smiled as the power settled into her body and began to react. Just like her friends, her muscles grew in waves, pushing out in all directions with intense bursts. Only for Amanda, her muscles seemed to grow audibly as her skin had trouble keeping up with the muscles growing and with her height increasing. Amanda had inched up the height dial but had dramatically increased the muscle on the gun.

Amanda’s legs exploded into twin pillars of jacked up muscle, blasting out in every direction. Her calves flared out beyond 20 inches in moments and her thighs pushed out to 18 inches wide. Amanda’s shorts ripped and tore and within moments were nearly engulfed by waves of super sized thighs and glutes. Amanda was wearing a thick t-shirt without a bra, since her breasts were practically non-existent. At least they used to be. Smiling as her back thickened and widened to previously unseen dimension, Amanda giggled as the shirt was tearing like tissue. Pectorals and rock hard breasts blasted into prominence. Steel hard nipples began to tear holes in her shirt as her upper body continued to surge forward. Her arms bulged ominously, splitting the sleeves with unflexed biceps and horseshoe shaped, rippling triceps. Amanda sighed with pleasure as she could feel her strength build with the muscles.

One hard inhale finally did the overstressed shirt in, exposing the mind numbing array of muscles exploding across her frame. Her height increased to 5 foot 8 and beyond. And as she grew taller, her muscles expanded even faster! Already more muscular than Sarah, Amanda was easily as muscular as Bethany, but was still growing bigger.

Bethany looked at the gun to see just what Amanda had done, while Sarah’s eyes widened. She had grown big. Bethany had grown even bigger. Now Amanda was putting both girls to shame. As her height neared 5 foot 10, her muscles were now bigger than any male bodybuilder could even dream of. Amanda’s muscles bunched and flexed like huge boulders across her feminine frame.

And still she grew bigger. Amanda smiled with delight as muscles previously seen only in comic books flexed to monstrous proportions. As her height topped out at 6 feet, Amanda brought her right arm up.

“So Bethany, how big do you think your arm is?”

Bethany looked at her massive right arm and flexed it into an intimating mass of muscle. “Oh I don’t know, 25, 26 inches.”

Sarah looked at Bethany with jealously and nodded her head. “Yeah, I’d agree.”

Amanda giggled as she tensed her mighty arm. Her bicep exploded upward into a mountain of muscle, the likes of which had never been flexed before. Her peak towered up toward her wrist. Hell, it looked like her muscles had muscles!

“Then how big do you think MY muscle is?”

Sarah and Bethany went slack jawed. Sarah blinked first. “That thing has to be 36 inches around easily!”

Amanda turned her head and looked at her bicep. She then flexed again and her muscles crackled. Her already mega sized bicep inflated, pushing her forearm away and sending the peak up over the top of her fist.

“How big?”

Sarah choked. “Holy crap Amanda! Now it must be nearly 50 inches around! I wouldn’t believe it if I wasn’t looking right at it!”

Amanda smiled as she pulled her arm down. She stood there as the biggest, strongest, most muscular girl ever. Bigger than any bodybuilder. Stronger than any man. This was beyond her wildest dreams. Sarah and Bethany walked over and tried to push against Amanda’s muscles, feeling the hardness. Amanda giggled with delight.

As the girls finished admiring each other’s new bodies, Amanda heard the doorbell ring. Her eyes sparkled. Those were Robert’s friends. They were going to be lifting weights out in the garage. This seemed like a great opportunity to try out their new muscles. She also looked at the differences in sizes between them.

“Well girls, those are Robert’s classmates over to work out. What do you want to do?”