As Lisa schemed away at the Chronivac, Eric went about his day. He had a second babysitting gig at a different house from the day before, the kids were overall well-behaved, which was a good thing given his state of mind. He couldn't stop worrying about Lisa, the trouble they were both in, and some of the looks he'd briefly seen on her face. But he was confident everything would work out in the end.
The day wore down, the parents returned in the evening, and Eric drove back to his house. He set down his bag inside the door and took off his shoes. "Mom, I'm home!" he yelled. Hearing no response, he tried again. "Mom?" He briefly poked his head around the house but couldn't find any sign of her, other than her car in the garage and some grocery bags near the front door. Why hadn't she put them away?
Growing more apprehensive, Eric glanced upstairs. The lights were off, but he could see a soft glow coming from his bedroom. Fearing the worst, he clambered up the stairs as quietly as he could. A strange, musky odor came wafted to his nose and grew stronger the higher he climbed. Something about the smell made his horsecock begin to stiffen involuntarily and snake down his pantleg, and he silently cursed his earlier experimentation. As he reached the top of the stairs, soft noises could be heard coming from inside his room. Bracing himself, he pushed the door open.
"Welcome home, Eric," said a voice from behind his computer. It was Lisa's voice, and yet not quite Lisa's. The screen's glow cast an odd shadow on the rear wall. The shadow moved as his desk chair rolled out toward the center of the room.
"Lisa?!" Eric cried, staring at a scene out of a nightmare.
Sitting on his desk chair was a nude Lisa, it had to be, but she was something between woman and rat now. Now more than a few inches shorter, she was coated with varying amounts of patchy brown fur, thickest across her shoulders, sides, and thighs. Her hands, feet and chest were mostly exposed skin, but it had a different quality to it -- not that he could see that well in the dim monitor light -- but it almost looked leathery. There were blotchy discolored areas, showing where her fur might grow in at a different shade from the rest. Her breasts had shrunk further into A cups, while the rest of her teats had grown, thicker and with a slight sag. The worst was her face, now with an unmistakable short rat muzzle, whiskers, broad rat ears poking out from underneath still-blonde hair. She grinned, showing off her longer incisors. The blue-white light from the monitor did her no favors, reflecting in small points off her beadier eyes.
"Ta-da!" Lisa said with a showman's flair, and spread her arms wide. Her fingers that had been so slender were now a bit knobbly like a rat's, and her carefully pedicured nails had become short claws.
Eric gaped at her in horrified disbelief. Before he could say anything, a soft "schlorp" sound broke the silence between them. A fleshy rope slipped out from inside her pussy and dangled off the front of the chair...the beginnings of her tail. Cum gushed out of her slightly-gaping slit afterward.
"Oops!" she said with a giggle. "I got bored waiting for you to come home and was playing with the new goods. It's reaaally nice but it'll be much better once it's longer, though I don't think it'll ever be a substitute for the real thing. Anyway, whaddya think?"
Eric was speechless. Lisa smirked. "Oh come on, don't be like that, we both agreed we'd indulge some of our crazier fantasies with this thing. I still haven't done that much with the Chronivac, mostly I fucked Tomtom a whole bunch of times, made him full size and we used your bed...might've tweaked some mental settings, libido stuff, cum production...I lost track of time, and then your mom came home, and..."
Eric interrupted her there, unable to contain the disgust in his voice. "W-where's my mom?"