LLuna was terrified. Judy Hopps had clearly lost her mind. While Lluna was a vixen and Judy was a bunny, the sheer sexual need that Judy exhibited was insane. The bunny had become so horny, so corrupted, that she was even able to enact physical changes to herself. Judy had been a female, like Lluna, but as the bunny went crazy with lust, Judy's crotch had grown a large, furry sheath and heavy sac of balls. 
Judy shoved Lluna back against the lockers. With a moan, her new cock sank into Lluna's pussy. The bunny's belly and breasts bloated slightly larger as she began to fuck the fox, her butt and footpaws pumping and plumping in size as well. Lluna cried out. She could feel the changes taking hold in her own body, too. Her own pussy and balls swelled bigger, growing to match the bunny's.
Lluna's cock and balls popped free of her red fur and swung out, rubbing against Judy's leg as the two animals fucked. But then Judy pushed away from Lluna, breaking their embrace.
"Fuck my ass, you sexy vixen!" the bunny begged.
Lluna's eyes bulged as her mind tried to catch up with her body. Judy's aggressive sexuality was corrupting Lluna's body and mind too. As the bunny bent over, presenting her fluffy tail and puckered asshole, the vixen found her hands moving on their own. Her right paw grasped her cock, the other her balls. She felt so fucking pregnant as her gut grew, too.
"That's right, baby. Pound my tight little ass. Fill it up with all those fucking puppies you got in your nuts."
"Y-Yes!" Lluna gasped, not understanding why she was saying yes, but wanting to resist. But then her cock speared the bunny's pucker and her willpower crumbled. She fucked Judy's ass, their heavy, swollen balls slapping together between the bunny's spread thighs. Both of their pregnant guts swelled larger, and their big tits spurt milk.
"Yes, baby. Breed me! Impregnate me!"
The two animals came at the same time. Lluna's balls and dick swelled even bigger, and she felt an enormous load of cum shoot into Judy's asshole. It was more sperm than the vixen had ever imagined she could make, and the load never stopped. She could feel the thick, white goo splurting and spilling into the bunny. Judy's stomach bloated and her tits spurted more milk as she came, too, her ass clenching around the vixen's cock and balls, her cunt gushing onto the floor.
It was almost a minute before they finished cumming. When they finally did, Judy turned around and kissed Lluna on the lips. She rubbed her belly, which looked even larger and more pregnant than the vixen's, and laughed.
"You've impregnated me, Lluna. You've knocked me up with all your hot, fertile seed."
"No!" Lluna sobbed. She didn't want to be pregnant. She was only eighteen years old. She wanted to go to college. She wanted to do something with her life. And yet, even as she sobbed, she felt her cock growing hard again. Her balls had not emptied themselves. She was still horny.
"Your turn now," Judy said.
The bunny pushed Lluna against the locker and the vixen felt the rabbit's cock sink into her own ass. She moaned, her tongue lolling out as her eyes crossed and rolled up into her skull. Pleasure unlike anything she'd ever known overwhelmed her.
"You're a pregnant fox whore, Lluna. Everyone who mates with you is going to become me, another Judy."
"No," Lluna said weakly, even as she came. Cum spurted from her tits and cunt as her stomach grew even more bloated with Judy's seed. She could feel her womb being filled, could feel the bunny's eggs being laid inside her, fertilized and growing into new Llunas and Judies.
"And I'll breed everyone," Judy giggled. "Zootopia will become a city of bunnies and vixens, and all of us will be me.
The bunny began to fuck the fox's ass harder.

---

Outside the locker room, Nick Wilde peeked in. He'd been watching the whole thing. It had been difficult for him not to get involved. The sight of Judy Hopps's body, of her big, pregnant gut and huge, swinging tits and balls, had made his own cock grow so hard that it ached. He wanted to fuck Lluna, too. And he'd been ready to, too, his cock popping free of his pants and swinging heavily as he approached the two females, but then Judy had spotted him.
With a giggle, Judy bent over and spread her ass and pussy. She began to give birth, to a fresh new Judy Hopps, naked and looking eagerly at him. He stared as she slipped out and landed on her big feet, proudly sporting a foot-long erection and perky breasts. She seemed exactly like Judy, but as Nick watched, she was getting both younger and a lot hornier. Musk rose from her body, and pubic fur sprang from her crotch and sheath. 
"Do you like how young I am? Pervert."
The new Judy waggled her fluffy, black-tipped tail and giggled.
Nick stepped away from the locker room.
"I'm sorry, Lluna," he whispered. "I can't help you. I can't stop this."
He was already so horny. He'd gotten a boner, just from seeing Judy fuck the vixen, and his cock had stayed hard ever since. Now the new Judy had her paws on it, and Nick was powerless to resist. He could only hope that the two of them would leave soon, and that he could somehow stop the two Judys before they fucked anyone else.
But deep down, Nick knew it was hopeless. They would fuck everyone. Judy had infected Lluna. The fox was pregnant with Judy's seed, and that meant the vixen was a Judy, too. Soon, Lluna would find someone to infect, and the infection would spread, and Zootopia would become a city of pregnant, horny, breeding bunnies and vixens.
Nick didn't even care about the world anymore. All he cared about was that he, too, would be turned into a Judy. That was the only way he could be with the real Judy.