“Well, here goes nothing,” The squirrel anthro sighed, tipping their head back and swallowing the little pink pill. It slid down their throat with ease. Riu sat back in their couch, wrapping their large, fluffy tail around their body, and subconsciously scritching behind their ear. In one paw they held a generic, unmarked bottle, very nearly completely filled with identical pink capsules. Riu wasn’t sure what to expect, if they were honest. 
They had chosen to wear older, less-nice clothes. The shorts barely even buttoned anymore, and the shirt clung tight to their furry torso. Riu hopped to their feet, unable to keep still, incredibly anxious in spite of themself, and scurried to the bathroom. They examined themself in the mirror, neither pleased nor disappointed with what they found. Or perhaps more accurately, both pleased and disappointed. 
They were large for a squirrel, about 5’11”, not incredibly thick-set, but hardly twiggy either. Riu raised their right arm, flexing their bicep. They were proud of their body; nearly a year ago they had decided that they wanted to be buff, goddammit! And Riu had pursued that goal admirably, going to the gym near daily, increasing their caloric intake and the amount of protein in their diet. But they just weren’t getting the results they wanted; they had gained some weight (hence the increasingly tight wardrobe), but it just wasn’t enough!
If Riu was honest with themself, they wanted to be big. Like. Really big. That’s where the pills came in. 
They had no real faith in the things, but secretly they desperately hoped they would work. Their tail twitched behind their head, the curse of all squirrels: endless fidgety energy. Riu allowed themself to indulge in narcissism for a moment, posing in the mirror, adjusting their dyed red head-hair, and flexing different muscles. They were a bit obsessed with their chest; after months of no real change, recently they had developed subtle pecs, and in their tight shirt, they actually showed (at least somewhat). 
Riu was boning up, and in their old, undersized shorts it was hardly comfortable. They adjusted their bulge, the tight fabric of the shorts showing their erection clearly. Riu’s dick was a painfully average 6 inches, yet another part of themself they wanted to grow. They gently massaged their bulge, imagining themself with a 12 inch dick, twice their actual size. But why stop there? They had had some, well, “encounters” with horse anthros as big as 16 inches, but even that almost didn’t seem big enough to Riu. 
They stopped. Well, it’d been about 5 minutes, and no catastrophic changed had happened to their musculature. They guessed they’d been duped into just getting a bottle of sugar pills. But just as Riu was thinking this, a sudden wave of nausea rolled over them. They felt dizzy, and their vision blacked out for a moment, like they had stood up too quickly. Riu placed a paw against the bathroom wall; somehow he’d become drenched in sweat in only moments, and their breathing was ragged.
Every muscle in their body suddenly ached. Their fur stood on end, and their perpetually moving tail was stock still. They felt their claws scratch the wall. Wait, what? Riu examined his paw; they were certain they were not moving, yet they could see the tips of their digits ever so minutely expanding across the wallpaper. It couldn’t be. Their heart leapt, and they looked themself in the mirror.
No doubt about it, Riu was growing. They could see the tips of their ears, inching ever so slightly upwards, and (much more importantly) their muscles were expanding. Riu lifted up their tight shirt; whereas before they had had a more-or-less flat belly, the extraneous flab was melting away, and rockhard abs, visible even through their chestnut fur, grew in its place. They flexed their their arm once more; their bicep already noticeably thicker, more cut, and vascular, stretching the fabric of the old tee-shirt’s sleeve. 
The nausea and aching had passed, and as the growth became more visible, Riu felt immense pleasure. The bulge in their shorts was also expanding, the outline of their still-erect cock stretching further along their hip. Their overworked tee-shirt now clung tightly to their expanding chest; their nipples pointing out through the fabric. Only moments ago, they had merely been a heavier-than-average squirrel, but now they were a 6’2” gymrat (gymsquirrel?). But their growth was only speeding up. Riu’s shorts, now only reaching about half the way to their knees, were completely filled by their thickening quads. They began to run their hands over their body, feeling their warm muscles growing. Their clothes were now being actively stretched by their expanding body; their pecs now that of a bodybuilder, their biceps bulging out like softballs.
Riu grinned, and once more flexed their arms, both in tandem this time. It was a beautiful sight; the pose emphasized their widening torso, and as they hit the pose, a loud rip tore through the air. Their expanding triceps and biceps had blown out the fabric of the shirt, leaving long, irregular tears up to their armpits on both sides. Their cock was throbbing in its prison, the massive shaft now reaching all the way to their hip. They grabbed the neckline of the ruined tee-shirt, and pulled with all the force they could muster. Their claws initiated the rip, but their muscles did the work in rending the fabric, tearing the whole thing off their torso. 
Riu allowed the fabric to fall from their paws, leaving their furred, massive torso bare. The pressure on their legs from their undersized shorts was becoming nearly painful, but Riu only reveled in that fact. They were now closer to 7 feet than 6, and had the appearance of a professional bodybuilder; pecs incredibly well-defined, and overhanging their rockhard 6 pack. Their shoulders were twice the width they once were. 
They grabbed the waistband of their shorts, and grunted as the attempted to rip them off. The fabric was much tougher than the shirt’s, but as they exerted their newfound strength, the shorts were rent apart. Riu was not wearing underwear. As they tore the fabric away from their front, their ironhard dick sprang out. It was fucking massive, at least a foot of hard cockflesh jutting out from their groin. Their balls were even more impressive, dangling in their fuzzy sack nearly to their knees, the size of baseballs. 
Tentatively, as if the whole thing might disappear and reveal itself to just be an illusion, Riu reached for their throbbing erection. Their paw closed around the burning hot, still-growing flesh. They moaned. Just the sensation of their soft pawpads against their dick felt amazing. Slowly, they began to jerk their meat. 
They were so huge. All their dreams were coming true at once. With their free paw, Riu felt their heavy pec, pinching their erect nipple, groaning at its sensitivity. They increased the rate of their jacking off, pounding at their 14 inch cock with wild abandon as their height breached 7 feet tall.
God, they were so big! So much bigger, so much stronger, than they used to be. Their cock was so massive, bigger even than most horses, or even elephants! And they still had a whole bottle of pills left.
The mere thought of the small vial of magenta capsules was enough to make Riu jizz. Their oversized, orange-rivaling balls drew up in their sack, and a mighty jet of cum blasted out of their cock, splashing against the bathroom mirror. As they reached orgasm, their growth magnified 100 fold, and as they came their height shot up rapidly, their dick forced their paws grip to slacken as it widened and lengthened. But more than anything, their muscles exploded, pecs expanding out in front of them, biceps becoming so large their arms were forced out from their body, quads like treetrunks, and calves that put moose to shame. 
As their cock gave its final, heavy pulses, their growth slowed and stopped, leaving them 8’2” and built like a brick shithouse. Fuck, no a cinderblock shithouse! Their cock rivaled their earlier fantasy, a full foot and half of squirrel dick, still achingly erect and drooling the last vestiges of their prodigious orgasm. Riu panted, their fat, massive pecs heaving with every breath. They were gigantic: the biggest squirrel ever, probably.
They needed more.
They burst out of the bathroom, slamming the door open so hard that it literally burst off its hinges, slamming to the ground. Riu didn’t give a fuck, really. They made their way back to the couch, and more specifically the coffee table where they had left the pill bottle so cavalierly. Their oversized tail, much larger than they were used to, knocked a stack of papers off the nearby counter. Riu tore the lid off, and bringing the bottle up to his muzzle, swallowed every last pill inside.
Some part of them knew this was probably an awful idea with far-reaching consequences, but this part was easily overruled by the part of them that had desperately wanted for so long to get big. The effects took much less time to kick in this time.
No sooner had Riu smacked their chops, the capsules leaving a bitter, dry taste in their mouth, than they felt once more the sweeping wave of nausea, and the dizziness. This time though, it felt much milder, and almost instantly passed to be supplanted by the pleasure of growth. They shot up towards the ceiling, the rate of expansion orders of magnitude greater than before.
“FUCK YES!!!” They couldn’t contain themself. Their still-hard cock had grown to 2 feet in the mere 10 seconds since ingestion, and already their head was but inches from the 10 foot ceilings of their apartment. They hunched, muscles so large that they competed for space on their body, growing so quickly that they were forced to their knees simply to prevent themself from giving their upstairs neighbor an unwelcome surprise.
That couldn’t last long though, as they were filling the available space in their small apartment rather quickly. Only moments later, on their knees, and head bowed, back pressed against the ceiling, their 6 foot dick growing dangerously close to the wall, Riu decided fuck it. They pressed up with their immense strength, and like soggy cardboard their plaster ceiling collapsed as they burst through up to the 4th floor.
Almost as if responding to their loss of inhibition and concern about collateral damage, their growth increased. Their muscles were growing just about in proportion to their height, preventing complete immobility of their limbs, but they were damn close to it; arms so fucking thick that they were forced out at 45 degree angles to their body even once they had created a hole in the ceiling large enough to lower them to their sides. Still on their knees, their head reached more than half the way to the ceiling of the floor above them (the apartment whose floor they decimated apparently unoccupied). 
Riu groaned as their cock came in contact with the outside-facing wall of their apartment. The rigidity of their cock was so incredibly vast that they flexed it just a tad, and the whole wall, plaster and brick and mortar, exploded outwards, releasing their titanic dick into the outside air as it blasted past 10 feet long. 
The floor beneath them gave a slight groan, and without any more warning the structure beneath them buckled. On their knees, Riu fell through the floor to the 2nd floor, and then the first, the whole building shaking violently as they destroyed precious parts of its internal structure. 
Riu figured the whole place was only its last legs anyways, so he rose to his feet, any part of the building he came in contact with bursting apart from the force of his massive body. He punched a hole in the facade of the apartment complex, bursting out of the building. Literal tonnes of brick, steel, wood, and probably more than a few anthro bodies tumbled into dust behind them as Riu stepped out onto the street, their head now about 5 stories high. Their cock was already pressed up against the building opposite them, and grinning madly they thrust their hips forward, cock punching into it, destroying much of the 3rd floor. 
They turned, cock leaving a trail of destruction in the poor building as it forced its way back out into the open, pointing straight in front of Riu as they began to walk the thoroughfare. At their feet, tiny citizens rushed about, fleeing the growing macro. Cars screeched to a halt or swerved, chaos reigning as Riu callously crushed anything in his path, leaving the ruined, mangled remains of cars and the bloody streaks of slow-moving pedestrians. They laughed, the deep boom of their voice echoing through the shrinking city.
Their head eclipsed all the nearby buildings as they strolled casually towards downtown proper. Even the tallest nearby building (a 15 story, high-end apartment building) was now shorter than the 200 foot squirrel. Their cock, still growing disproportionate to their body, now stretched in front of them 100 feet long, and drooling precum, leading to a veritable flood for the tinies below. 
Riu was now walking blocks a second, their monstrous footpaws leaving indentations and spiderweb cracks in the weak pavement beneath their impossible weight. Their oversized thighs rubbed against each other with every step; their tail so huge and powerful by itself that when they on whim struck a building with it much of the face crumbled. 
As they waltzed into downtown, Riu was finally faced with buildings that could actually dwarf him once more. But not for long. They stopped in front of one particularly impressive office complex, the tallest in town, in fact, standing at 56 stories and 683 feet tall. Only barely taller than Riu at this point. 
Well, they figured they had to indulge in their favorite macro trope: grabbing the sides of the skyscraper, they took their cock (nearly 3/4ths their own height), and plunged it into the towering building. It burst out the other side, sending a barrage of glass and steel shrapnel raining down on the panicking populous. Almost instantaneously, the building buckled, the top half tipping over and crashing into the ground beside Riu, leaving their dick woefully unserviced.
Figures that reality doesn’t line up with fantasy, they mused. Instead they wrapped both forepaws around what they could manage of their massive shaft, and began to pump. Despite their inability to reach about half their dick, the thing had become so sensitive as it grew, that they felt sexual pleasure beyond anything they had experienced before. And they still grew.
Riu widened their stance, feet crushing an entire city block as they surpassed the height of the (formerly) tallest building in the city, stretching up to heights far beyond it. They were bigger than they ever thought possible, bigger than any living thing on the planet, they were a fucking god compared to these fucking ants still scurrying at their expanding feet, futilely trying to escape their inevitable death beneath Riu’s soles. And they were nowhere near done growing yet.
The precum that Riu’s dick now leaked endlessly was so voluminous that those trapped beneath it drowned, and it flooded the yet-undestroyed city streets to a height of several feet. “I NEED!” Riu panted. “TO GET! BIGGER!!!” As the final word boomed from their mouth, the intensity and depth of their voice enough to shatter all windows within a several hundred foot radius, their body exploded. They shot past 1000 feet, the tallest buildings in the city (those that hadn’t collapsed yet, that is) barely up to their hip, and very quickly shrinking below that. Their dick’s growth finally fell into stability with their body, the monstrously thick shaft now almost equal to them in height, their massive furry balls as thick as their legs were long, just barely not touching the ground. 
A thousand feet turned into 2 thousand, Riu’s stance widening as their feet crushed entire blocks, snuffed out hundreds of lives without any effort. It was only fitting; mere mortals should make sacrifices to their god. Every muscle on their body was flexed, and expanding more rapidly than they could comprehend. Their pecs alone could house multiple city blocks on their expanse, and their arms held enough power to destroy whole countries if they so chose. And they weren’t done; they’d never be done. 
They shot past a mile tall, the city at their feet a mere doormat, not even enough to wipe their feet on anymore. The surrounding countryside stretched out as if they were looking out the window of an airplane. Growing bored of the tiny, ruined city upon which they tread, Riu began to trek north, each step carrying them a thousand feet, each step destroying hundreds of hours of labor. 
North of the city was nothing but rolling hills; hills that beneath Riu’s feet were but mounds. Laughing, they broke into a run, each bounding step sending tremors hundreds of miles in each direction, footpaws leaving deep craters in the earth behind them. 
In only a minute they traveled a distance that took 3 hours by car, their head now in the clouds at 2&½ miles tall. In front of them, they saw the largest metropolitan area in the state, a sprawl of multiple cities and towns and suburbs and millions, even tens of millions of souls that were completely at their mercy. Or, really, their lack of it. 
Riu dropped to their knees, holding their body-sized cock up off the ground with one paw, their monstrous balls forcing their legs apart and crushing the countryside behind them. “HEY PUNY MORTALS. PREPARED TO BE FUCKED BY A REAL GOD.” They boomed, and let go of their dick. It slammed into the ground with incredible force, destroying almost all of the downtown area in of itself. Then Riu began to thrust, their 3 miles cock rubbing against the ground, grinding everything in its path into the dirt. 
Millions of anthros were crushed beneath the impossible dick of the growing titan. They passed 4 miles tall, their dick keep pace as they thrust ever harder, fucking the earth itself with their cock. 
It was all too much for the expanding muscletitan. Their cock convulsed, their massive testes contracting as their dick spurted its load, their jizz flying through the air for miles, before crashing down in puddles that decimated entire towns. 
As before, their orgasm triggered a cascade of growth. They were mindless, humping the ground with all the force of their hypertrophied muscles. Their height doubled in mere seconds, before the first shot of cum finished ejecting from their rapidly expanding cock, and it just kept coming. There was nothing left of the city beneath them, their 10 mile dick having destroyed all of the urban area, their body crushing every surrounding town, not a single person surviving the destruction. 
Their cock shot again, the second spurt barely less powerful than the first. Riu shot past 20 miles tall, the cities and towns beneath them now just grey splotches on a green background. It was beyond looking like the view from an airplane, the ground beneath them now looked like they were seeing it from a satellite photo. 
They panted, each breath like a tornado the microscopic landscape below. Their cock throbbed more, the cum now drooling out, billions of pounds of jizz crushing what little remained intact beneath Riu’s titanic, expanding body. 
Finally, it ended. Their muscles relaxed, their fur laying flat against their impressive, impossible musculature once more, their knees now lying in a lake of jism to rival the Caspian Sea. 
Riu rose to their footpaws. Their head was now far above even the highest clouds, the earth beneath them just more ground to be torn up and destroyed. They were over 50 miles tall, hundreds of times taller than even the tallest skyscraper, their height dwarfing even Mount Everest. Riu flexed hard, and their body responded, expanding another mile into the air in only a moment. 
They grinned. It wasn’t gonna stop now.