Jim pushed open the door of the changing room, almost but not quite having to duck for the doorframe which was stupidly set at an average 6'8" height which was more the average height of guys who shopped here, at least the tall ones. And Jim was tall, 6'7" and a bit, but he was resigned to hitting 6'8" by the end of the summer and getting ready for a lifetime of ducking for doorframes.
Of course, "Big and Tall" was pretty much a misnomer. The store should have been called "Fat and Fatter, with the occasional clothing for big fat guys" but there was nothing for rake-thin skinny guys who were not filled out and probably never would be.
There was something greasy on the door as Jim pushed it open, probably sweat from some fat dude who's squeezed his way in, and the 7' ceiling was even more claustrophobic. Jim set down the pants he wanted to try on then kicked off his shoes, stepping around as he shucked off his too-short jeans and then stepping on something. Something wet. WTF?
He looked down. Someone had left their old clothes in the changing room along with what looked like a bottle of sunscreen or something and he'd stepped right on it, making it spurt lotion all over his other foot and leg. The skin tingled on contact and there was a smell of herbs.
Jim reached down to smear the stuff off, but there was a lot of it and nothing to wipe it off onto, so he decided to rub it in instead. It's not like it was going to be poisonous or anything and he was planning to go to the beach later anyway.
It smoothed in and rubbed on and a second later he found that his leg hair was coming off in his fingers. It was a hair remover! Great, last thing he'd wanted.
Then his muscles started to seize up and swell, larger and larger and he watched in the mirror as he went from Jim the scrawny lanky surfer to Jim the 6'7" muscle god. What on earth?
He didn't know how it had happened, but his prayers had somehow been answered. He was suddenly big enough width-wise to get clothes that fit, and it was all muscle too. Then he paused as his head suddenly tapped the 7' ceiling.
Jim kept growing taller, the muscles becoming proportionally less as he regained his former lanky form, but supersized now. He was 7'10".
Then the last part of him supersized and his cock dangled down to his knees and his balls were now the size of small melons. "Oh my god," Jim rumbled, doubled over in the now-tiny (if aptly named) changing room.