Becka made the first mistake she had made all day. She paused. Instead of wrestling the gun away from Amanda, she watched as her sister began to transform.

Amanda had received her initial shots in short bursts, growing her muscles bigger. Becka had received one semi long burst and then another, longer one, making her bigger and super strong. But Sharon was receiving her initial burst continuously. The fresh, fully powered radiation flooded into the moaning Sharon with untold levels of strength and power. The visual results of Sharon’s ascension were spectacular. Her voice was commanding as her entire body radiated energy.

“You were right about one thing Becka. The fresher the radiation the better. And I’m receiving a full on dose from the first pull of the trigger. You thought you were powerful. Just you wait. Your Ultra sister is about to show you a thing or two! I can FEEL the power pounding in my muscles. I can sense my strength increase geometrically! Soon I will be the queen bee around here! The super muscular queen bee!”

As the stunned spectators looked on, they had to squint as Sharon’s entire body crackled like a sparkler on the fourth of July. Her muscles pulsed, tensed and grew rapidly, splitting her shorts quickly against raging, mega muscular thighs. Her shirt and bra didn’t just rip off her growing body, but burst into flames as electrical discharges sizzled the fabric brighter than lit magnesium. Her shoes, socks and panties quickly followed suit in a bright, electric visual display until every square inch of her naked, throbbing body was exposed for all to see. Muscle fibers pressed to the surface across her frame like steel cords of pure energy as they absorbed unthinkable power. The ultimate muscle fibers then multiplied, making Sharon bigger, stronger and sexier than anyone would have thought possible.

“More power! More might is pounding, swirling and growing into my waiting super muscles! There isn’t a being alive who will even be in my class! I’ll toss air craft carriers around like toy boats! I’ll destroy mountains with a single punch!”

As the radiation continued to blast into Sharon, each breath popped muscles on to her abs that no one watching even knew existed. Her chest became awe inspiring. Thick, striated pectorals surged forward, backing up massive steel hard breasts that pressed forward without a jiggle. Her nipples elongated as an electrical discharged surged between them. Sharon’s long blonde hair moved around with static electricity sparks. As her back widened and thickened beyond male bodybuilder size, Sharon pulled her arms out to the side and lightly tensed her fists, rolling super muscles across her forearms, to her horseshoe triceps to her football shaped, unflexed biceps to her surging shoulder and traps and across the thickest set of pectorals any of them had ever seen. And as the group stood there stunned, Sharon slowly rose until her feet were no longer touching the ground.

“You see girls. This is the REAL potential of the gun. To receive the pure, unfiltered, original radiation at its peak. I’m already more powerful than both of you combined to the point that I can now resist the pull of gravity at my will. Can you do THAT Becka?”

Becka took a step back. Amanda tried to release the trigger. She tried to point the gun away from Sharon, but even with her newly acquired strength, she was unable to do either as if Sharon now controlled the very radiation that continued to pore into her. Sharon laughed.

“And you put on quite a show there with your big muscles, Becka. Think I can flex up a bicep as big as yours, little sister?”

Sharon pulled her arm up and her bicep literally exploded upward, radiating power with the ferocity of a hurricane and blasting higher as if bowling balls were being stacked under her skin. Amanda’s hair whipped around and she was pushed back hard into the wall. Becka took a several steps back until she too was pressed against the wall. As Sharon chortled, a two foot tall bicep quickly ripped up to four feet tall and then smashed through the basement ceiling and into the floor above with a loud crunch. Sharon smiled at the other girl’s reactions of awe.

“Gee. I guess I can! This baby looks to be about 6 feet tall! Now isn’t that just ridiculous?”

Amanda swallowed. “Sharon. I can’t seem to release the trigger. You’re growing too powerful.”

As Sharon released her bicep flex, her body continued to snap and crackle as pure power was discharging against her mega muscled form. Her muscles glowed brightly as they continued to pull in unthinkable level of strength and might.

“Too powerful? There’s no such thing! But I suppose that I’ve proven my point.”

With a final flex, Sharon pulled in the last of the radiation and allowed the gun to stop firing. Amanda released the trigger and rested the gun in her lap, sighing with relief. Sharon gently landed back onto the ground.

“Now little sister. The last thing I remember you doing to me was blowing me across the room with a puff of breath. Whatever shall I do to repay you?”