Brux was bigger, heavier, and stronger than most other rats -- so big he even put some preds to shame. Above all else, the huge brown rat loved working on his body, always getting larger and mightier, and even fatter. For Brux, it was all about weight. Pure mass.
No one understood him, because he wasn’t like most other furs. He didn’t spend every day pumping it at the gym out of a desire for fitness, or strength, or even for attractiveness. No, what drove Brux was the fact that there were deep and dark terrible things that one could only achieve if they had the body for it.
As Brux tugged on the rowing machine, eyeing the cute couple standing by the weight bench a few metres in front of him, some of those evil things were dancing around his mind right now. He smiled to himself as he listened in on their conversation, just audible over the gym’s music.
“I want to give it a go!” one of them said, nodding at the bench. He was a slender, feminine kitty, whose name seemed to be Dylan, and he was a little cutie.
But his boyfriend, a quite attractive deer with dark black fur, was standing there with his arms crossed, shaking his head. “I just think you need to start on something easier first, babe. I just don’t think you’re… you know. I don’t think you could do it”, he said, smiling sympathetically. The deer, named Josh, was much fitter than his boyfriend, and the loose tank top he was wearing showed off some decent muscles. He was obviously more experienced with gym equipment than the eager cat, who seemed to be here for the first time.
Dylan huffed and sighed unhappily. “I’m sick of being a little wimp”.
“We’ll work you up to it, don’t worry”, Josh replied, rubbing his smaller boyfriend’s shoulder. “Now I’ve really gotta piss. Why don’t you hop on the treadmills? I’ll be back in a minute”. He took one step away before stopping to warn, with a hint of humour in his voice and a smile, “Don’t do anything stupid before I get back”.
“Mm-hmm”, Dylan said, curling his lip into a pout.
Brux watched the deer enter a corridor leading out of the main room from the corner of his eyes, and then he made his move. 
The muscle-bound rat stood up and wandered past the grumbling cat, playing it cool, as though he hadn’t been spying on them for twenty minutes now. As he passed by he let out a curious grunt, and stopped to tap the cat on the shoulder. Dylan span around, face to face with Brux’s bulging chest, before twisting his head upwards to catch the rat’s eyes. The kitty’s own eyes were round and wide like saucers.
“Just saw you lookin’ at the weight bench”, Brux said, smiling warmly. “Need a hand? I’m always happy to help out a newcomer”.
“Oh…” Dylan said, his own face warming up at the kind gesture. “That’s nice of you, but… I’m not sure I’m strong enough”. He glanced over his shoulder at the bench with disappointment.
“Oh, hey! Don’t be like that!” Brux chuckled, giving the cat a gentle shake via his shoulder, before winking. “A positive attitude is how you get a body like this. I believe in ya. Why don’t I spot you, to make sure it’s safe, and you can give it a go?”
The cat’s face lit up. “Really? I’d really like that!”
“Hell yeah!” the rat laughed. 
“Sweet!” Dylan grinned.
The huge rat led the tiny cat around to the side of the bench. “You lie down on top. I’ll load up your weights for you”.
While the cute kitty lied down, Brux glanced around the gym. There weren’t many furs here today, and those that were here were lost in their own little worlds. In fact, no one was even looking in their direction. He turned his eyes to Dylan from where he was standing at the foot of the bench, and she cat was grinning eagerly, so thin and short that his entire body was on top of the bench padding. “I’m ready!” Dylan said.
“Great”, the rat replied, though in a lower tone than before. Looking down at the small creature below him, he felt a rush of power through his powerful muscles. This was why he worked out. This was what his massive body was for. This was what made him happy.
He turned around to sit down on the edge of the bench, and quickly fell backwards. 
In the space of a second, Brux enveloped the smaller male underneath his flesh, squishing him between his back and the bench. Dylan instantly started struggling against him, but the rat was just so big and heavy that he wouldn’t budge. Brux grinned silently to himself, closing his eyes peacefully, as he felt the kitty’s limbs squirming in fear against his back, ass, and thighs. He felt the dull vibrations of stifled moan against his upper body, but Dylan’s face was so covered that he barely made a sound.
Brux let out a satisfied sigh, gently shifting his body around to make sure the kitty was trapped underneath him nice and good, while his fat cock throbbed inside his shorts and started to tent the fabric a little.
Then he heard the clop of footsteps behind him, and shifted his head to look behind himself. The black deer had returned and was looking around the room for his boyfriend.
“Hey dude!” Brux called out. “Can you give me a hand loading weights up for a few minutes?”
Josh wandered towards him. “Oh, uh, I was just…”
“Oh, you’re looking for the kitty cat? I think he went over to the treadmills”, Brux added. Conveniently, the treadmills were in a different section of the gym that you couldn’t see from here.
The deer looked reassured. “Ah, cool. Well, I suppose I can help you out for a few minutes”.
Brux grinned, unflinching as he felt Dylan scream silently against his upper back. “Awesome”.
The bench was soft enough, and Brux had enough fat on him, that Dylan hadn’t been crushed to death by the rat’s sheer weight already -- he was still kicking and struggling underneath him. But Brux could sense the cat’s bones trembling below his own. If the rat weighed just a little more…
“Let’s start out with a hundred pounds?” Brux suggested, smiling secretly to himself.
“Sounds good”, Josh replied, starting to load weights onto the bar for his gym buddy.
As Brux braced and pushed the bar into the air above his chest, he could feel the weight pushing downwards through his arms, transferring into his poor little victim, whose bones he could almost sense creaking. Dylan’s movements grew more frantic, while Brux’s cock grew harder.
“Another hundred?” the rat panted.
Each time Brux pumped the two hundred pounds into the air, his cock throbbed hard. With so much weight in his hands, Dylan was almost entirely immobile, and the rat soaked in the terrible power he had over his victim. The exertion, and his vicious lust as well, was working up a sweat, and he imagined the cat gasping for air and getting nothing but musk while soaking in sweat. “Mm, this is great. Shit”, he grunted. He couldn’t imagine how horrifying it would be for the cute little kitty.
“More?” Josh asked. The kind deer had no idea he was literally helping the rat crush his boyfriend to death. 
“Mmm. Yes”. 
“Heh. You’re a beast, dude”.
Three hundred pounds, and Brux’s cock was tenting hard with a wet spot at the peak, flexing uncontrollably in time with his muscles. The burn through his bulky arms was as good as sex, but Dylan’s suffering was even better. The weight was so intense he was sure the cat was about to give any second. But astonishingly, he persisted -- Brux could still feel the pressure of squirming limbs against his flesh, and the skull wriggling between his shoulder blades. He didn’t want it to end, but he knew Dylan had to be close to suffocating, and that wasn’t how he wanted the cute boy to die.
“Grrr! Let’s go for five hundred”.
“You sure?”
“Fuck yeah”, Brux grunted. 
Josh chuckled, loading his buddy up with enough weight to kill a cat.
Brux rested his hand on the newly loaded bar, and took a moment to look up at the oblivious black deer and smile happily. It would be so nice to revel in how wonderfully fucked up the situation was, but his cock wouldn’t let him -- pulsing hungrily inside his shorts, threatening to blow, begging him to do it.
He gripped the bar and raised the weights into the air, roaring triumphantly. “Rrrrarrrgh! Fuck!”
CRUNCH.
It was far too much for the little femboy. Dylan’s skull collapsed beneath the rat’s spine, his ribs snapped in rapid succession with little pops, and his pelvis crumbled.
“Whoa, dude, you alright?” the deer asked urgently, his eyes open wide. “Sounded like something broke then!”
Just the sound of your boyfriend dying.
“I’m fuckin great, dude!” Brux groaned, thrusting the weights into the air and letting them fall downwards against his muscular body, feeling the cat squish, crack, and flatten underneath his tremendous weight. “Feels so fuckin good… Ughh! I’m gonna… Ugggggggghhh!” His fat pulsing cock exploded, thick seed oozing through the fabric of his shorts with every throb, while Brux let out a long, wordless groan -- the pleasure of a crush snuff flooding his body, amplified by the fact he was doing it right in front of his victim’s boyfriend.
He heard Josh laughing nervously, and noticed the deer staring at his crotch. “Uh, you really enjoy working out, huh?”
Brux gritted his teeth in a grin, staring up at his buddy while his cock continued spurting. “You, mmngh, like that fuckin shit, dude? Why don’t you get down there and slurp it up?”
Josh blushed and laughed nervously, but his eyes didn’t turn away from the rat’s cock as it dribbled and drooled the last of his powerful orgasm. “Maybe if I didn’t have a boyfriend”, he replied in a low voice, slowly licking his lip.
Brux broke into laughter at the irony.