Leading a Horse to Water

Story by Burst on SoFurry

, , , , , , , , , , ,

Casey is an overworked mustang who's been fortunate enough to be invited to his weightlifter cousin's lakeside cabin for a weekend of boating, sunbathing, and tubing. When a sudden bout of self-consciousness hits him, his attempts to throw together a last-minute beach bod lead to disastrous ramifications... for his cousin's cabin, at least.


Casey stood against the wooden railing and stared out at the expansive lake before him, taking in the unseasonably warm autumn air. The mustang sighed pleasantly. This was his first time at a vacation home, and even though the cabin wasn't his, but his cousin's, he was already looking forward to the weekend. Work had kept him practically chained to his desk lately, and getting himself away just long enough to spend a few days drinking beer and sunbathing was a coup in itself. The warm weather helped the mood immensely; he could feel sweat beginning to form amongst his acorn-colored coat as he took in the morning sun.

The trees across the lake were still in full fall colors, blazing red and orange in the rising sun. The other vacation homes and boat docks of Lake Laughlin completed the view, filling out the horizon in both directions. His cousin's speedboat sat docked down below him, the bright yellow inner tube he'd hopefully be riding on later in the day lay on the dock, glistening with dew. Casey scratched at his neck, the cheap fabric of his work polo itching as it tended to, and imagined himself riding on the tube behind the speedboat, grinning slightly, before glancing down at his watch. Just a few more hours.

Yawning, Casey walked back inside, past the tiki torches and citronella candles, through the screen door to the sunroom. The cabin wasn't too big, but made the most of its lakefront location, with a huge, screened in sun porch to compliment the deck and serve as the de facto living room. Heading back towards the driveway was the kitchen and eating nook; the bedrooms were downstairs in the split-level, opening out to the lakeshore. The sun porch also had a smattering of workout equipment on it, what with a combo bench/squat rack, a stretching or yoga sort of mat area, and an elliptical. The entire room was wooden, with paneling on the walls and hardwood beneath the foam floor mats.

Casey picked up his Dunkin's cup from where he'd left it when he'd arrived. What little coffee was left inside was cold and gross, as he expected. He'd have to see if he could brew some more. Hopefully his cousin had a K-cup maker, he'd brought K-cups, and it'd keep him from having to scrounge for filters and grounds.

On the back wall of the sunroom were a number of photos of his cousin Larry at what he presumed were different weightlifting competitions. Venice Beach, Columbus, Miami. In each of the photos, Larry looked absolutely, ridiculously enormous. The older mustang's dark brown fur barely hid his tank-sized frame; massive pectorals bulged from the front of the competition singlets, with almost impossibly bulky, vein-covered arms hoisting up the weights. Casey gawked momentarily, drooling slightly before reminding himself with a shake of his head that this was his cousin. He knew Larry was a competitive weightlifter in his spare time, but hadn't kept in touch too well. He'd never actually seen him compete; he didn't realize he had ever gotten THAT huge.

Yet at the same time, there was no way he trained with just what he saw here in the house. There weren't nearly enough weights in here to support that kind of a body, and the last time he had video chatted with Larry, he hadn't seemed that huge. Maybe he was just like the boxers and MMA guys that dropped a ton of weight in between events? Casey pondered, before shrugging to himself. Eh, it wasn't his business how he pulled it off, but he had to admit, he was a little envious.

Larry was supposed to show up sometime later in the morning, returning from some business trip the day before, and then Larry's girlfriend and his other-other friend, neither of whom Casey knew too well, would come for lunch. Barbecues and taking the boat out on the lake were the plans for the day, but after seeing his cousin's competition photos, Casey suddenly felt like he might as well be wearing a t-shirt to the pool, if he was going to be out in the sun next to a big, muscular hoss like his cousin.

The mustang wasn't tremendously out of shape by any means, though again, it depended on who he was comparing himself to. Casey was easily the most in-shape person at his job, but in any field, sales folks weren't particularly known for being bastions of wellness, so that... wasn't the best metric, necessarily. He'd done track and cross-country in undergrad, like practically every other equine that he knew, but that had been years ago, and too many take-out lunches, too many nights out drinking with the clients, and just the sheer monotony of being on the road so much had taken its toll.

Okay, so he was a little flabby. He hadn't touched weights for nearly two years since he'd let his gym membership expire, and the majority of his fitness had been a half-hour here or there on hotel treadmills whenever he could find them. It wouldn't be nearly the issue if he didn't know that Larry and his girlfriend were both fitness fanatics, and he'd be shirtless around them later. It was an odd but expected sort of self-consciousness, though it did make him wish he hadn't let himself go so much.

He checked his watch again as he walked back towards the kitchen. Larry'd be here in a half hour, it looked like. Casey left his coffee cup on the counter as he snooped around the kitchen, looking for a coffee maker. Next to the fridge sat a black wooden bookcase, with what seemed to be an entire GNC's worth of different fitness supplements all over it, all in the usual eye-searing colors and holograms he'd come to expect from that sort of thing. Two protein shakers sat by the sink in the drying rack.

"Hmmm..."

Casey's mind began plotting, as he opened the fridge out of further curiosity. Inside was about what he'd expected for a mass-gaining weightlifter: a ridiculous number of egg cartons, a couple gallons of whole milk, and interestingly, what appeared to be a lab rack of small, individually labeled and capped test tubes. It wasn't unlike what he'd seen when he'd had his blood drawn at the hospital before, yet instead of holding blood, each tube held an iridescent, almost glowing yellow liquid. Yet another holographic label adorned the plastic tubes. He didn't recognize the name of Sounder Bio-Athletics, but if anything, they certainly looked expensive and... a little suspect.

He snickered to himself, as if this confirmed what he'd already slightly suspected after seeing Larry's competition pics, though he did wonder if whatever this... substance was, was legal for competition. Not that it mattered to him, it wasn't as if he dared to press the issue. There were no instructions around that he could see, but if he had to guess, based on similar products he'd seen, he figured the vials were some form of pre-workout mix. Granted, the packaging was a bit different, and they certainly wasn't as obviously labeled as C4 or NO Explode, but he'd seen enough of that sort of stuff in his college days that he was pretty sure he knew what to look for.

There were enough vials in the rack, he didn't figure Larry would notice if he snuck one out from the back. Looking it over in his hands, the liquid seemed to bubble not unlike citrus soda as he moved the tube back and forth in his fingers. The warning label took up nearly the entire rear side of the tube, but he figured it was probably the usual bit about caffeine and heart palpitations and stuff. He was still young enough, and the coffee had been long enough ago, he didn't figure there'd be an issue.

Taking the tube in one hand, Casey left the kitchen and headed back towards the sun porch. He recalled offhandedly how he'd read that movie stars and reality show people would do a quick weight set before filming just to make all their muscles pop, and although he wasn't sure he still had muscles TO pop, it sounded better than nothing. Maybe if he was lucky he could make himself look more bearish in build, he mused, but his normal frame was too probably naturally skinny to pull it off. Heck, he was pretty much just doing this for his own psychological benefit anyway, as he doubted they'd notice his muscles 'popping' no matter what he did.

Casey sat the vial down near the weight bench, before walking back to the front door and dragging his suitcase out into the sunroom. He still needed to change out of his travel clothes anyway. Zipping it open, he rummaged through the clothes inside, trying to find his swim trunks, occasionally glancing down at his watch to make sure he still had time to do this impromptu workout without being walked in on like a goof.

Quickly pulling his work polo over his head, he swapped it out for an old, faded Myrtle Beach t-shirt, which, he noticed, was so frayed and worn he'd probably have to donate it after this trip. Not that anyone would probably want the tacky, pseudo-tie-dyed thing. Undoing his belt, he dropped his khakis and boxers together, leaving him briefly bottomless and letting his black tail fall free, before he pulled up his blue and black swim trunks. Adjusting his junk momentarily and tying the drawstring, he felt, for the moment, still kind of fat.

Shoving his clothes back in and zipping up the suitcase, he took a seat on the bench and turned his attention back to that little vial. There was no serving size, no nutrition facts or anything. Once again ignoring the warning text, he twisted the cap, hearing the pop of the seal breaking, and looked down into it.

A strong medicinal smell wafted into his nostrils, with a sharp citrus undertone. The liquid fizzed slightly as it was exposed to the air, bubbling not unlike an opened can of pop.

"Eh, we'll see what this does," Casey thought, before downing the vial like a shot.

The liquid tasted somewhere between hyper-concentrated Kool-Aid with the piercing artificial bite of sort of lemon cleaning solution. It burned like he'd done a shot of rye whiskey, with an odd underlying fizzing sensation as it went down. Already he felt the vague muscle tingling characteristic of pre-workout mixes, a sort of screaming urge in his muscles to hit the weights, to pump iron, just to release the tension in some way, shape, or form.

Casey was practically quivering where he sat as he laid the vial aside, his vision blurring slightly as seemingly every part of his body picked up the buzz. He squinted, trying to regain his focus, laying his form back on the bench and looking up at the bar sitting on the rack. He hadn't done a bench press in years, and hoped he could at least do a ten-rep set with the bar. Bracing himself, he lifted the bar off the rack, waiting for his arms to collapse under the weight... and then blinked in amazement at how unnaturally light the 45-pound bar suddenly felt.

The tingling through his body seemed to subside momentarily as he completed his warm-up set, the ten repetitions seeming to get easier as he finished them. Strange, he thought, as he slid off the bench in search of more plates to add to the bar. "Larry, I don't know what's in that stuff, but if this is your secret, I'm totally cool with that," he said, to no one in particular. He bent over to hoist a 25-pound plate, and nearly flung himself backwards with the momentum. The plate felt like it weighed practically nothing, which was even more uncanny. He continued to ignore it for now, tossed the plates on, locked on the clamps, and lay back down.

Two reps into his next set, he could feel his chest already aching, the good kind of ache, that he remembered from long ago, with the tingling sensation of the pre-workout mix returning, concentrated mainly on his pecs and his arms. As before, the weights only seemed to get lighter the further into the set he got. Was he in better shape than he had thought? There was no way. He looked at his watch. Fifteen minutes till Larry. He had time to go even harder, get those muscles to pop even further. But first...

Rolling off the bench, Casey darted into the kitchen, oblivious to the fact that in the five or so minutes since he'd started lifting, his torso had already quietly began to tone up. His gut no longer hung quite as far over the waistband of his trunks as they had, his upper arms weren't quite as flabby underneath, but the sheer easiness of the sets he'd done was blinding him, narrowing his focus even more. Flinging open the refrigerator, the horse reached up and pulled another vial from the top shelf, popped it open, and chugged it without a second thought.

The taste wasn't as bad the second time, still acrid and lemony, but the tingling and dizziness hit him like a brick to the face, nearly making him stumble over. Rubbing his eyes, he braced himself against the doorframe of the kitchen as a brief vertigo spell hit him. As it subsided, the post-whiskey sensation remained; he could feel the heat and electricity course from his core out into his extremities, a sensation he'd never quite felt to this extent.

"Alright, let's try the forty-fives," Casey said with an uncharacteristic confidence. The horse dashed back into the sunroom, the muscles of his body practically begging him to lift. The 45-pound plates felt almost like lifting phone books, such was their seeming lack of heft, as he simply added them to the bar without taking the smaller plates off. Sliding onto the bench and positioning himself underneath, he braced himself, breathing heavily, and pushed. Even with this much weight it still felt as easy as when he'd started with just the bar. He could feel a tiny rumbling building in his chest, in his arms, and oddly enough, even in his legs, but he dismissed it as, if anything, the pre-workout reacting with the coffee in his gut. He huffed as he completed his fifth rep of the set, still consciously trying to pace himself as to not drop the weights from pushing too fast, grunting as he pushed the bar up once again. "Six..."

His vision began to blur slightly again as he lowered the bar back down. "Seven..." His body trembled, his chest heaving, as he gripped the bar and, with an abrupt, explosive burst of strength, pushed upwards. The bar left his grip like he'd pushed against air and rocketed straight up, crashing through the ceiling with a blast of drywall dust and wood splinters. Before he could even process what happened, he heard the barbell slam back down somewhere outside.

"What in the fuck?"

Casey sat up in surprise, rolling off the bench, before yowling in surprise as a blast of that same tingling sensation rippled through him like an electric shock. His entire body rumbled, shivering as if he were in a freezer yet broiling like he'd hopped into a furnace. Now panting, he collapsed to all fours as it seemed like every sweat gland in his body was about to gush out. He exhaled hard, before moaning as his form suddenly began to change, growing abruptly in all directions.

The Myrtle Beach t-shirt stretched and strained as the equine's chest pushed out first, his formerly flabby chest suddenly solidifying with muscle mass, surging as countless new fast-twitch fibers formed. The edges of his sleeves began to rip as his biceps and triceps ballooned outwards as well, the changes propagating down his forearms and up to his shoulder and into his back. His watchband popped under the strain and flew across the room. Casey heaved, gasping to take more air into his increasingly voluminous lungs as his entire upper body filled out, the fat on his midsection being consumed and reformed into a new, concrete-like slab of core muscles. His acorn-colored fur became more and more visible as his shirt, by now resembling a cutoff singlet top, finally ripped away and fluttered to the floor.

Casey kept his eyes shut as the changes continued, newly generated muscle rippling from his core down through his lower body. His hind end surged outwards as his glutes filled with muscle and sinew, his burgeoning quads ripping through the edges of his swim trunks until his trunks now resembled a posing pouch. Even his hoofs felt the surge, expanding to keep up with his still-growing frame. As he staggered to his feet, his vision finally clearing, he felt his midsection quiver suddenly, before a wave of pleasure shot through him. Whatever was happening to him wasn't quite finished yet. Casey stood up fully, and swore as his head banged into the ceiling. Hunching over slightly, he now noticed the bulge that was tenting outwards from his tattered swim trunks. The adrenaline and testosterone racing through his body, plus the surprise and pleasure at this newfound form, made the next choice of actions fairly obvious.

Grabbing hold of the shreds of synthetic fabric and yanking them aside, he revealed his increasingly burgeoning equine cock. Now freed, his mottled pink length hung nearly to his knees, and he wasn't even all the way hard yet. He grunted harshly, as another hot wave of pleasure passed through him. His heart racing, his freshly massive hand took hold of his equally massive, basketball-sized nuts, giving the sand-colored sack a good squeeze. His shaft began to fill with blood, his nads churning tumultuously with seed as his body still continued to grow.

His monstrous cock was now fully filled, fully grown out, pre already dabbling at the not-quite-yet flared tip. Casey, catching his breath, paused to look over himself, even as his throbbing cock begged for his attention and even as his head began to press into and crack the wooden ceiling. He cringed at the slight, dull pain as he could feel his bones adjusting and growing with his frame, his osteoblasts frantically synthetizing all the new bone mass needed for his tremendous form. Below him, the floor began to bow and buckle from the countless mass he'd gained in the last few minutes.

Solid, meaty shoulders the size of beach balls met up with his bulging traps and his thickening neck, his acorn fur thin enough to show off all the bulk, all the definition. His chest was two huge boulders of granite with a canyon in between, such was the intensity of his pectoral mass now. Looking down, he glimpsed more than a six-pack, losing count of just how many abdominals he had gained as they tapered down to his groin. Glancing over at the pictures of Larry on the wall, he realized with a slight hint of fear that he'd grown even bigger than his cousin's competition size, and, as he noticed crumbs of drywall tinkling onto his shoulders, that he still hadn't stopped.

Yet any paranoia, any worries of that sort were immediately assuaged the instant he looked down and saw the enormous, beefy telephone pole that was his cock, standing hard, standing proud. Wiping his black mane out of his face, he licked both of his hands and brought them to the base of his massive shaft. Hefting his member up, he realized it was now easily huge and long enough to lick himself, without having to bend over or anything. His nuts twitched and tingled at the thought as he slowly brought his shaft towards his muzzle, the crown of his cock now glistening and dripping with musky pre.

With a moan, Casey lapped up the pre at his tip; his own musky taste was intoxicating. He'd been nearly able to suck himself off, long, long ago at his track and field prime, but that was still an 'almost', and he had never been able to stay excited long enough to taste his cum after fapping, so this was a tremendously welcome change. Gingerly taking the tip in his mouth as best as he could, he suckled, letting off a garbled, guttural moan from the stimulation. Streams of pre now trailed from the corners of his muzzle, while he ran his massive hands up and down the increasingly slickened shaft. Each stroke sent another surge through his body, and each surge pushed him harder and harder against the ceiling and floor. The scent of his musk permeated the sunroom, wafting through the house, his excitement and pleasure escalating with every second.

His tongue smacked against his cock as he struggled to push his shaft further in, gagging slightly as the giant tip pushed against the back of his throat. Rivets of pre continued to pour from his muzzle, the fluid matting into his chest fur and parting like streams down his the mountains that were his chest and core muscles. His heavy, hanging nuts tensed as he neared a climax, shivering with a pleasure that again reverberated through his enormous body.

Stroking his mottled length with both hands, it suddenly happened, an eruption of equine seed, a veritable geyser of musky cum that shot out of his nostrils and gushed from his muzzle, his cock pushing its way out of his mouth before he could flare up. A feverish euphoria rocked Casey's body, as each stream of cum shot its way out from his throbbing cock. With each quivering pulse, the horse now grew at an exponential rate, blasting his way through the roof right as the floor of the sunroom finally gave way under his size. Wood, shingles, and ceiling tiles crumbled around him as he ripped upwards through the cabin, stumbling backwards as the orgasm continued, sending the kitchen collapsing downward into the new hole in the ground where the sunroom had been. The weight bench and exercise machines, lying in a heap amongst the boards and timbers, were pulverized under his hoof as he inadvertently stomped on them, struggling to maintain his footing.

Another heavy rope of cum shot out, now splattering the dock, the speedboat, as Casey continued to expand, stumbling his way down the shoreline, leaving colossal hoof prints in his wake. He stepped out into the lake, feeling the cool waters of Lake Laughlin meet his hooves, the water now barely coming up to his ankles, his cousin's boat rocking like a pool toy from the splashes and waves he was making. He'd turned around now, facing back towards the wreckage of the house, just in time to see the fridge and Larry's shelf of weight supplements tumble over into the debris pile. The pulses through his flared cock were less intense now, the orgasm tapering off, his still-hard cock still gushing a seemingly endless supply of cum from the tip, cum which had almost entirely blanketed the boat dock and was now pooling inside his cousin's boat. The rest of the cum now floated on the lake waters, a white splattered trail from the ruins of the house out to where he stood, now unmistakable, a towering equine colossus easily visible from the entire lake.

Casey panted, moaning slightly as he caught his breath, before instinctively recoiling as his deep, guttural moans boomed across the lake. Still half-heartedly stroking himself, his tremendous, monster cock still nearly touching the waterline as he stood in the lake, he began to try to process what the hell had just happened. He looked down over himself, monumental now as he was, cum-matted fur and all, and cracked a smile. This wasn't, well, remotely what he'd had in mind when it came to making his muscles pop, but... it'd do. The mega-sized horse stretched out, admiring his immensely powerful, gigantic form, his house-sized biceps, his cliff-sized pectorals, before, out of the corner of his eye, he saw a now-tiny blue car pull down the driveway towards the eviscerated vacation house.

Oh right, Larry.

The BMW's door opened, and his older cousin frantically dashed out. Casey squinted; his cousin was at least as muscular as he'd been in the competition pics that were now somewhere in the pile of sunroom wreckage, but at the same time, he was small enough in comparison now that the gigantic horse could probably hold him in one hand. Casey couldn't quite hear what Larry was saying, standing as high as he was, but he could tell the darker brown horse wasn't the happiest camper. Casey paused, ignoring the swearing and cursing for a moment, wondering how he'd even begin to try to explain what'd just happened.

"LARRY!" he spoke, with a thundering, echoing voice that ensured everyone in a ten mile radius heard him. Cripes, that was louder than he expected. Come to think of it, an explanation might be a little difficult.

On second thought, maybe he was better off not even trying to explain.

Casey grinned, a guilty, yet shameless grin, and offhandedly gave his cum-covered hand a lick. It was certainly going to be an interesting afternoon.