Bruce the bull murrs quietly to himself as he enters a simple building with no windows, his thin tail wagging softly behind him as he joins a line with many other folks like him, which were fair sized critters of many species that are all here for one reason. They were all asked to come here to try a new clinical injection that promised to make them studs beyond their wildest dreams. They even showed pictures of successful before and after pics of even the scrawniest of guys becoming hulking men of muscles! There wasn’t even much to lose as the price was very low, no more than 10 dollars to get one. It couldn’t hurt to try, even if it did nothing. The line passes through quickly, and soon he himself was next into the room.

Inside, there was a doctor with a needle in his hand full of something white in the syringe. He explains what to expect as he did his work. “Now, it’ll take a few hours to work once it enters your bloodstream, so go ahead and do your daily work as it were any other day. You’ll feel some tingling, which is normal and will tell you when the growth spurt will start. Heh, you might want to be outside when this happens as the growth can be quite exponential. Otherwise, enjoy what’s to come.” He pats the bull’s shoulder once he’s done and sends him off to the exit.

Afterwards, the day is mostly a bore as the bull has a quiet work day with nary anything exciting but a quiet heat he could feel in the crotch of his pants, and finds himself popping random boners to his male coworkers, some who were in that line too. “Perhaps a side effect of the drug, kinda like Viagra or something where it makes you more arouseable.” he thought to himself. It certainly wasn’t helping he wore a tight shirt and pants and underwear that clung to his already athletic body. After work, he went to the gym to get a quick workout in, heading to the weights to pump some iron.

Bruce put on 225lbs on the bar and put it behind his head and starting doing some squat lifts, grunting softly as this challenged him just right. But a few reps in, he starts to feel the tingling sensation mentioned by the doctor, though not on his arm, but in his balls. It was a warm sensation to be sure as it felt like his balls were filling with more bull spunk, complimented with a tent in his pants as his dick begun to stiffen again. He tried to ignore it and continue doing his workout, but each squat he did make the tingling sensation spread throughout his whole body like a pulse of a heartbeat, oddly making him want to do more reps rather than stop. He let the sensation guide him, as he felt his muscles get warm as well and start to tighten and release in time. Before he knew it, his muscles and even his junk began to grow inch by inch, confirmed with each passing second of his clothes getting tighter and tighter. Through 100 reps, his bulging pecs and arms, legs and manhood ripped from their cloth confines with loud enough noise that the others in the gym watched in awe at what was taking place. They saw the hefty bull grow into his new form, with arms and legs as thick as steel beams, pecs so swollen with muscle they were probably way past any cup for a bra size never invented and shoulders as massive as well that his head was sunk in them some, and dick and balls so massive, it would snap any underwear and looked like two overinflated beach balls to the point of bursting and a redwood tree of a cock. He was nearly reaching the ceiling with his new height. Its enough that everyone, male and female, blushed at the sight of pure perfection and they came over to the bull and started to touch him all over.

Bruce mooed softly as he was pleasured by the gym crowd, almost like a worship of the muscle god that he was. This new form was quite sensitive, especially to his huge member and bloated nipples that he had gained as well. It was no surprise that his dick got nice and veiny and stiff and started to leak pre. However, his hard nipples were leaking the same precum substance as well, almost like they were breasts filled with cum instead of milk. His audience licked it up happily, wanting to taste his nectar so badly. With a mighty moan and bull moo, his nipples and cock erupted with streams of thick ropes of cum all over himself and his new fans. They ate it up happily, even getting soaked in the spunk and rubbing it upon themselves, hoping to appease their new master. The bull smirked with a wide smile as he was going to enjoy this, and felt another tingling in his hyper-sized loins, suggesting another growth was imminent.

As the bull grew even huger still, his fellow worshippers earned growths of their own, bulking up nicely to be muscular hunks in tight clothes with big, wet pecs/breasts and lower parts. From that day on, they saw Bruce as their god, bowing and worshipping him before every workout and taking a protein drink of his cum daily for the gains. Any new followers that came to the gym were introduced to Bruce through his cum first, then get their membership by getting fucked by the bull’s massive cock and getting pumped full of his seed to give them a big starting gain, so they’ll want to come back for more and pleasure Bruce for more. He happily grows from then on, getting milked for his spunk and growing massive every day, even bigger than the gym eventually and becoming a skyscraper of muscle himself.

A while after his appointment as beef god to the gym members, one of his new members surprised Bruce quite literally when he drank his cum and had quite an explosive growth himself nearly like the bull’s. As he drank and grew, he saw the special member was a jet black male panther, turning into quite the hunky muscular stud himself. In near minutes, the panther was equal sized to Bruce in muscles, height and even junk, who patted the feline’s head to stop so they could speak.
Bruce: “My, aren’t you an eager one? What’s your name?”
The panther: “Derrick, my liege.”
Bruce smiled: “Derrick. My subject, may I offer you a deal of a lifetime?”
Derrick’s eyes widened: “Really? What is it, my king?”
Bruce: “Would you love to be my queen for life?”
Derrick: “Yes! I would be so happy!”
Bruce smirks: “Shall we consummate it then?" The panther’s head nods fast "Then turn around and let’s do it.”
The macro sized panther turned and showed his mammoth sized ass for the macro sized bull, and quickly, Bruce’s loins surged harder than it ever was before. Holding the feline’s thighs, he softly guided his cock into that tight asshole, Derrick moaning all the while as he slowly got that whole scepter right up his ass and bulging out his belly with a shadow enough to cast over the entire city. Compared to the sucking from his subjects, Bruce took gentle care to be slow and deliberate with fucking his new Queen, who rode that cock slow as well, wanting to enjoy his leader’s cock. They made the passionate love making last an entire day, till Bruce’s loins were churning so heavily with seed that he couldn’t hold back any further, erupting geysers of potent cum into Derrick’s boy hole. Of course, Derrick himself basically made a whole lake of his cum by the end of it all. After all was said and done, Derrick was left with a hyper extended gut full of his god’s seed that oddly didn’t leak out once he pulled off. To both of their surprise, 9 months later, the duo made something special.

With nary any effort at all, Bruce and Derrick had little, mind you more like the 10’ tall kinda little, babies of bull, panther and inter-species offspring, and quite a litter at that of at least 20 kids of either gender and a few with both genders. All the subjects below worked in tandem to take care of their new king, queen and kids for the many years to come.