As soon as his mutated girlfriend left to go home Eric punched the the air in success!
Mission accomplished!
The once beautiful and gorgeous human girl had finally made the decision, of her own free will, to abandon her human form and embrace the change. To embrace the superior form of the rat.
Excitedly, with his rat cock already slipping from it's sheath he jumped onto the Chronivac, opening his folder of prospective Smelly Rat images.
The first one up was the last one he had created, a busty, furry, svelte anthro Rat with killer hips and piercing eyes.
"Oh that's a good look!" Eric commented, cock extending further. He came out of the folder and scrolled up, deciding which image to look up. Then something caught his eye, the first folder created, months ago, on the first day the then Lisa had changed, it was called research. He half remembered making it at the time to see where the mutation would eventually lead.
So long ago it was now that he couldn't even really remember what was in it, other than he was horrified.
"Wonder what it looks like now" he opened the first image. His eyes widened as in it Lisa, now Smelly Rat, was so mutated there was nothing human left.
A wretched hunched 3 foot tall furry rat mutant with beady eyes, claws, a ropey tail, and saggy duds glared back at him. It wasn't even a furry looking back, it was a Rat creature. Unexpectedly to Eric at the sight of it his rat cock slid fully free of its sheath and gave a squirt of rat cum, splattering the underside of the desk.
"Fuck" Eric grunted. The constant exposure to the Chronivac's possibilities and the escalation of his new found furry fascination had thrown him off the deep end very quickly. He did not expect he'd be so turned on by it, especially as the memory of them being horrified and discussed at it flooded back to him. Feeling shame at his actions he could not help but grab the extended shaft and frantically jerk it.
Ropes and ropes of rat cum began to vomit forth from the pointy, angry, red shaft. More, than he had ever cum before. More than he had excitedly dumped into his changing girlfriend the night before. This was on another level. His hips thrust into his hands, as he stood, chair falling behind him.
He could imagine it now, that rat bent in front of him, tail raised, sinking into her. Breeding her..
"Oh fuck!!" He slipped, foot sliding through slick cum. With a curse he fell, landing hard in a puddle of his own rat cum.
The pain of the fall snapped him out of it, cock softening and retreating, as he panted and grimaced.
"What the fuck..." now that the moment was over he felt ashamed again. He'd just cum over an image of his girlfriend barely more than an animal, and it had set off the biggest orgasm of his life.
He looked down at his rat balls and cock with a frown, had they caused it?
Looking around, it slowly dawned on him that he was lying in a significant pool of rat cum, the same substance that was permanently mutating his girlfriend. With a sigh he got up, carefully walking to the bathroom to clean himself off before anything took hold. Before he left the room however, he couldn't help himself but turn and look back at the image on the Chronivac again. He wondered then, would a time ever come that Smelly Rat ever looked like that. Maybe... With the right convincing... Well... It'd have to be her own choice of course. He looked at the Chronivac again... Then he shook his head. No. Not yet. Let's see where she goes by herself.
----
Not long after Smelly Rat was scrambling in her bedroom window. What Eric hadn't known was that Smelly Rat was on a descending journey of her own.
The trip back had been full of shocked people, far more so than any previous walk, as she scurried and scampered through the suburbs. Her heart raced, not just from the race through town. She was excited to show off her new form at home. Eric had asked if she wanted to reset her current look as the norm again, but she had declined. Wanting to see how they reacted, hoping that they would be shocked and disgusted by it. She was especially excited to see Sarah's reaction, her sister always being a horrible stuck up bitch, she wanted to rub this in her face. As it turned out she didn't need to wait long at all.
"Think you're soooo sneaky eh!" Her sister's voice called out. Smelly Rat yelped and fell to the floor in a heap. Turning over she sat, legs splayed, holding the side of her head.
"The fuck!!! What happened to you?" Sarah exclaimed. "Huh!?" Smelly Rat exclaimed from the floor.
"Your body!" She pointed as Smelly Rat cursed, they were supposed to be okay with her being treated like a rat. Only. She had changed since the rules had been set. "Fuck" she grumbled.
"You!" She pointed again. "Your face! You've changed!". Sarah stood as Smelly Rat hung her head and grinned.
"You're actually fucking changing now!!!" Sarah's face lit up in amusement and she cackled.
"You gross animal, I thought you'd never get around to changing your body, you've been banging on about it so long I always thought it was bluff. I didn't even know you could!" Smelly Rat was quite taken aback at how forward her sister was being, it immediately stirred memories of her dreams. "Ew... Look at those hands for feet, and the claws..." Sarah turned up her nose.
Sarah stepped forward, looming over her stunted sister, "no wonder you gave in, you were never going to get a human body with a gross mutant body like that, better you stick to your own ki... Are you... are you fucking horny right now!?" Sarah asked incredulously.
Smelly Rat let out a moan and dropped to her knees, her slit drooling. This was exactly like her exhibitionist dreams. Sarah took one step back, looking down at Smelly Rat in disgust and pity. Smelly Rat, in turn, was fast getting so turned on she was resorting to her base brain responses honed through months and months of sub play and shameful exhibitionist dreams. She began to grovel.
"Yes... Yes-yes... I'm a filthy rat... Your sister is a rat." She began playing with her own very numerous nipples, her eyes locking in on the giant rat cock dildo and the memory of being fucked by it. Not thinking too hard about what she was doing she scrambled across the floor to it. It felt exhilarating acting out so many of the vivid dreams she had. She grabbed the large rat dildo and placed it on the floor with a loud *slap*. She turned grinning to her sister. "I got fucked last night by a biiiig yummy rat cock like this one. The ratty cum from it is what's turning my body into its true form. I absorb it." She squatted over the top of the cock and, lining it up, sank bodily on to it with a sigh.
"Aaahhh... That's better..." She moaned. Her sister made a shocked face. "You absorb rat cum!?" She asked incredulously. "Hmmmm, yeeeaaahhh... That's how I found out I can turn myself into a rat, Eric and I were messing around with a reality altering machine for fun, then I accidentally did something stupid and irreversible." She ground her pussy around, impaled by the massive dildo. For some reason she wanted to be as candid as possible to her sister now, to bare all to someone. "It was only a small change first, could have lived my life at that stage pretty much normally. Only... I decided this is better!" She grinned wildly, bouncing on the dildo with wet slaps. "The more rat cum I absorb, the more I'll mutate. Forever.".
"That's, that's fucking crazy... You always looked ratty, even when we were small!" Sarah protested, clearly perturbed.
"Naaahhh", Smelly Rat cackled, "I look like this by choice... And... So could you if you wanted!?". Smelly Rat ventured. Sarah recoiled, "What!? You're sick!" She spat, turning crimson.
"Maybe I am! But I am reeeaaaallly enjoying myself, and, I think underneath all that bravado, I think you're jealous...". Smelly Rat cackled, then began really bouncing in the dildo, moaning loudly. Sarah looked affronted and went a shade of scarlet. Smelly Rat continued. "Ah.. Ah... I could find you... Ah... A nice big fat cock. Have you stuffed full of rat cum, and we could be the sexy anthro rat sister's? What do you think!?" She exclaimed, groaning loudly, then popping off the dildo with a wet *slorp*. She caught her sister's eye and there was a flicker, just for a moment, before she recoiled again.
"You're fucking sick you are..." she exclaimed then stormed out of the room. Grinning, Smelly Rat crouched down and mumbled. "You know what... I think you might be just as sick as I am." Before she picked up the wet dildo and began studiously licking it clean