As Brian looked at the blue substance his brother strolled in the room.
"Hey bro what you got there?" his brother asked
"Nothing Mark, just a protein shake but it is too sweet for me, But I know you like sweet drinks. Want it?"
"Sure"
Brian hands over the blue beverage to his brother, and Mark takes one big gulp.
"Man, what are you talking about? This isn't too sweet. Lets work out with the weights downstairs, I fell bumped from that shake."
They walked into the basement, in their spare time they would work out when they weren't swamped with farm work. Mark ran down stairs and ripped off his shirt and started doing all these different poses flexing his small muscles. They started lifting weights, Brian noticed something about Mark, he kept touching and grabbing his crotch.
"Hey bro, I don't think that protein shake really helped my muscles, but I think it did something else." said Mark.
Mark then unzipped his pants to show his brother his very recently obtained endowments. He pulled out his giant cock, Brian just stood in awe.
"Damn, that bitch gave me powder to endow myself, I should have taken it" Brian thought to himself.
Mark than started bragging about his recent luck, and then noticed something else odd. He was growing hairier, like he had armpit, pubic, chest and leg hair, but he didn't before.
"Hey Brian this shit is weird, now I am just flying through puberty, what is it?"
"Well Mark, you by now know that wasn't a protein shake. It was actually a powder mixture I got from this woman. She told me to take it, and claimed it would solve are problems."
"Well bro, you wussed out and gave it to me? Thanks man now I got the big dick and a better body, and you are just still some small boy. This is just humorous, all I have to say is hahaheehaw!"
Mark clutched his hands to his mouth instantly after hearing what came out of his mouth.
"Help Brian, I ain't feeling so wee-haww, hee haw!"
Brian watched in twisted amusement as his brother's ass started to swell, which led to his jeans splitting, shredding and falling to the ground. A stub was noticeable and quickly grew to a long tail with a black tassel at the end. The hair from his legs, chest, armpits and pubic area was spreading rapidly now and becoming dark brown fur. Mark was braying frantically and swinging his hands which were harden and darken into hooves, his feet were doing the same. Mark had trouble keeping his balance at this point and submitted to all fours. He than started braying and he sounded like he was in pain as his face stretched into a muzzle. Soon after the complete transformation Brian tried to calm him down.
"It is okay Mark, I didn't know this would happen. Don't worry tomorrow I will this woman and try to find a way to reverse it. If I can't though don't worry you do your work and I will buy you a nice jenny."
Brian led Mark to the empty stables in the back and apologized once more as he headed back to the house, leaving his jack ass brother behind. He than thought to himself,
"Tomorrow I will go see her alright, but instead I will another packet to transform my buddy Troy."
He laughed to himself as he entered to the house, who knows what will happen tomorrow.