Karl slipped the size 16 sandals on his feet. As he had guessed, they were too big. He gave a sigh and stared back in the mirror. Karl kicked his foot the get the flip flop off but it didn't budge. Karl continued to shake his feet to get the flip flops off. Puzzled, Karl began to pry it off with his other foot, but the sandals weren't budging. Karl began to lean down to remove them with his hands but it was then that his feet began to burn.
"What the..." Karl's eyes began to widen as he saw his feet slowly growing. His small feet began filling out the sandal quite nicely. Karl began moaning as the intensity grew. His hands flew to the neck of his shirt, tugging at it to give him more air. The heat grew and grew. Karl began to sweat profusely. His panting increased. He quickly turned toward the mirror and watched in slow terror as he felt the changes take hold.
"Please...please..ma..make it stop..." Karl panted words between each breath, realizing that he was growing. His legs extended, pushing upward. Karl grew from 5'2" to a tall 6' tall. But height wasn't the only change he experienced. His calves began to inflate, pushing out and creating powerful legs. Next his shoulders widened, his back rippled with muscles. His shirt began tearing at the seams. Karl moaned as his shirt finally gave way to his growing muscles. His pecs inflated, forming perfectly rounded muscles. His flat torso began to grow as well. His abs began to clearly define themselves. His hairless chest pulsed powerfully with his newly grown muscles. Next, his arms began to inflate. His biceps bulged. Karl stared at himself in the mirror, standing shirtless in the size 16 flip flops and shorts. His breathing began to slow and he believed the changes were done. But he was wrong.
Lastly, Karl felt a pulsing in his pants. He squealed as his ass suddenly flexed and firmed up. The muscles in his thighs began to tear through his shorts. As his shorts fell to the sides, Karl stared as his blue boxers began to tighten more and more. He lifted the waist of his boxers and stared in at his hairless, 3 inch dick. It was growing. His dick hardened and became erect, pressing up against his boxers. His boxers began to change color and turned a bright shade of red, shrinking and retracting in the form of a tight speedo. His now 5 inch boner was quivering as pre-cum dripped out of its head. Karl's moaning began getting louder and louder. His balls dropped lower and lower as they filled with hormones and cum. His 5 inch dick grew in girth, thickening. His dick began growing longer and longer, reaching from just below his naval to his mid-torso. His 5 inch boner was now an impressive 12 inches. Karl fell back and leaned against the wall. His dick was still pulsing and dripping pre-cum.
Karl's shaking hands reached forward to grab his new, massive dick. The moment he touched it, cum fired at his face. Loads and loads of cum fired repeatedly, some flying over the door of the dressing room. Karl screamed and moaned as ecstasy filled his body.
Meanwhile, outside....