Invasive Species

The office of Dr. Jennifer Hall was much like the woman herself—well-organized, clean, and efficient. Every spare surface had a vivarium of some type, filled with various snakes, lizards, and turtles.

Dr. Hall had asked Olivia to take care of her animals while she was away, and Olivia had happily obliged. She’d already done all the feedings for the week, so today’s work had just been double-checking that the heat was set right and everything looked in order. Realistically she could have left, but Dr. Hall had sent her a text asking her to hang around. Apparently she was finally back from the Amazon—a trip Olivia should have been on as well, if not for an untimely case of Covid. So now Olivia was sitting at the doctor’s desk grading some papers while she waited for her mentor to arrive.

She was deep into the grading, trying to determine if the paper she was reading was AI-generated or not, when the office door swung open. Dr. Hall was back, and she was pushing a hand cart that was loaded with a covered rectangular box, about three feet long and two feet deep. Probably another terrarium of some kind.

“Olivia. Thank you for taking care of my animals.” Jennifer Hall was a striking woman in her mid-forties with sharp features. She wasn’t the warmest person in the world—Olivia wasn’t sure she’d ever laughed in her life—but she was renowned in her field. She’d discovered two new snake species in this decade alone.

“Oh, it was my pleasure,” Olivia said. “They weren’t too much trouble. I still can’t believe you have a Fijian banded iguana.”

“He’s beautiful, isn’t he? It’s not legal as a pet, but I do have the permits for research purposes. He’s the second-rarest animal I have in here.”

“Second-rarest?” Olivia looked around the room, and then her eyes settled on the newest covered entry on the hand cart. “You found something, didn’t you?”

Dr. Hall smiled. “Do you want to see it?”

“Of course!” Olivia practically leapt up from the desk. What could it be? A South American bushmaster, maybe?

Dr. Hall pulled the covering off to reveal not a vivarium, but a cooler that she moved to her desk. So whatever she had was dead. Dr. Hall put on some thick gloves and carefully extracted a few dry ice packs and set them aside before pulling out a ziploc bag with… something inside.

It was a snake, or maybe a legless lizard with pale-pink, almost translucent scales. The creature was about 18 inches long, but almost as thick as her wrist and lacked any visible eyes, possessing only a patch of smooth scales above its small jaw. Its posterior didn’t taper at all, so either the tail was greatly reduced or conversely just as thick as the torso; it was hard to tell. Either way, the creature’s body terminated in a blunt, bulbous stump.

“Holy shit. What is that? It’s fossorial, I assume, since it doesn’t have eyes—and that stubby tail that kind of reminds me of a Mexican short-tailed snake. But it’s very thick for something that burrows.”

“Very good,” Dr. Hall said. “It is a burrower. But not in the dirt.”

Olivia pondered this. “In sand, then?”

Dr. Hall walked around the desk, stepping in close to Olivia as if to share a secret. Olivia could smell her perfume—a heavy, musky scent that seemed to fill the small room. It made Olivia’s head swim slightly.

“The locals steer clear of it. I believe it was once endemic to much of the rainforest, but due to habitat loss and modernization, there aren’t many left—maybe only a few hundred. It’s a shame. The locals believed it was a parasite, but in truth it has a mutualistic relationship with humans.”

“Mutualism?” Olivia looked at Dr. Hall for any sign she was joking. “Do you mean commensal? Like, they live in their houses or something? Reptiles don’t form symbiotic relationships with primates. Much less mutualistic ones.”

“No,” Dr. Hall said. “It’s an endoparasite, Olivia. It enters the host and resides within the uterus.”

Olivia took an involuntary step away from the thing. “That’s… that’s impossible,” she stammered. The scent was stronger now, distracting. “The immune system would reject it. And it’s too big, this isn’t a pinworm.”

The thought was revolting. There were so many reasons it shouldn’t work, but Dr. Hall seemed so sure. The expression on her face was one of excitement.

“Not for this species. It’s a marvel of evolution,” Dr. Hall insisted, stepping closer again. The musk assaulted Olivia’s nostrils, making her skin feel hot and prickly under her clothes. “It secretes a mucus that suppresses the local immune response without compromising the host.”

Olivia shook her head, trying to clear the fog. “But you said it was mutualistic. What’s the benefit?”

“Once inside, it feeds exclusively on the uterine lining. It keeps the endometrium perpetually thin. A woman hosting this organism cannot conceive. Think of the medical applications, Olivia!”

Olivia stared at the creature in the bag. She imagined that thing coiling inside her. It was a revolting thought, and yet the image of something slithering inside her, filling her up, was… no, she brushed the thought away. “That’s horrifying,” she whispered.

“Is it?” Hall challenged. “It is 100% effective biological birth control. No hormones, no pills, no surgery. Perfect for women in developing countries who don’t wish to become pregnant but lack access to regular healthcare.”

“It eats you from the inside,” Olivia countered, fighting both the nausea rising in her throat and the wetness building between her legs. “How do you even know its lifecycle? This thing is dead.”

“I know. It’s a shame they would kill such a beautiful, helpful creature, isn’t it?” Dr. Hall sighed, looking at the bag fondly. “I heard stories, didn’t believe it myself. But I followed the rumors and found a woman who was ‘infected.’ I saw it come out of her, Olivia.”

“You saw it?” The mental image was terrifying and yet alluring.

“The locals have herbal treatments that poison these poor creatures. They end up crawling out of their hosts before dying. Of course, I did contact tracing. I found where she’d ‘contracted’ it from.” Dr. Hall paused, her eyes locking onto Olivia’s. “It was very educational. Olivia, I have a live specimen too.”

Olivia looked into the eyes of Dr. Hall. She had an almost frenetic excitement in her expression. On one hand, that made sense—Dr. Hall had just made the discovery of the century. This wasn’t some random snake, it would rewrite herpetology. On the other hand, something just felt wrong. Dr. Hall was giving off a weird vibe. The musky scent in the room was getting stronger, making it hard to think. Olivia felt a strange heat between her thighs—a heavy, throbbing arousal that overwhelmed her body even as her mind recoiled.

She was turned on. God, she was turned on by a dead parasite. What is wrong with me? she thought, panic flaring. But the panic only seemed to feed the arousal.

“And the benefits don’t stop with birth control,” the doctor continued, her voice taking on a zealous edge. “It regulates you.”

“Regulates?” Olivia braced herself against the desk.

“The women who were hosts… they experienced heightened vitality,” Hall said, stepping even closer. Her face was only inches from Olivia’s now. “It releases dopamine and oxytocin directly into the bloodstream. It wants the host to be happy. It wants the host to be active.”

“Active?” Olivia asked, the word feeling breathy. She found herself staring at Dr. Hall’s lips.

“Sexually active,” the doctor said. The scent rolled off her in waves now. “You see, that’s the genius of it. How does a host spread a parasite that lives in the womb?”

Olivia shook her head, squeezed her eyes tight. “I don’t want to know.”

“It spreads through sex, Olivia.” Dr. Hall was standing so close now, their lips were practically touching. “When the host becomes aroused, the snake senses the blood flow. It uncoils. It pushes down through the cervix, which is always open in women that carry it.”

“Oh God,” Olivia gasped, inhaling more of Dr. Hall’s musk. The thought was disgusting, revolting, sexy, and beautiful. No, that wasn’t right. She had to get out of here. She tried to get away, to put the desk between herself and Dr. Hall, but her legs felt like jelly. She tripped over the chair, landing on the floor.

Dr. Hall continued to advance until she stood over her student. “Let me show you,” she said, unbuttoning her pants and letting them fall to the floor.

Olivia stared, transfixed, as a bulge appeared in Dr. Hall’s panties, growing larger and larger until pushed up and through them. It looked remarkably like a penis without a head, but one covered in translucent scales—as if some kind of novelty dildo were emerging from the woman’s vagina. Most disconcerting of all, it swayed in the air, moving independently of its host.

Olivia’s eyes went wide. The scent was suffocating now. Her panties were soaked, she realized, and she felt a deep, almost painful emptiness in her pussy that longed to be filled. She tried to get up, tried to run away, but instead all she could do was stare. Dr. Hall discarded her panties, letting Olivia see the full sight of the thing. The scales were smooth and wet, glistening with a thick, translucent mucus that dripped onto the carpet.

“Get away from me,” Olivia said, but made no move to leave. The musky fog seemed to bypass her lungs and go straight to her pussy. Every time she inhaled, the throbbing between her legs intensified, a desperate ache that demanded release.

Dr. Hall kneeled next to Olivia and began unbuttoning the girl’s jeans. “See? Your body knows,” she said. “Just like mine did. You can’t fight biology.”

As soon as Dr. Hall removed Olivia’s pants, the thing began waving wildly in the air, straining for the student’s opening. Dr. Hall gasped in pleasure as it wriggled. “It feels so good, Olivia. You’re going to love it too.”

Dr. Hall removed her own shirt and bra, and cupped her breast, playing with an erect nipple. Olivia looked down and saw her own nipples were hard as well, tenting beneath her shirt despite her sports bra.

“Please,” Olivia said, though she didn’t know if she was begging for the doctor to stop or to keep going.

Dr. Hall positioned herself between Olivia’s legs. The tip of the scaled cock brushed against Olivia’s entrance. Its texture was rough, ribbed with tiny plates that scraped against her sensitive flesh.

“Open for me,” Dr. Hall ordered.

Olivia squeezed her eyes shut, tried one last time to summon the will to leave, and instead spread her legs.

Dr. Hall entered her—or rather the creature did. It wasn’t like a man. It was harder, denser. As it pushed inside her, Olivia could feel the muscles of the appendage flexing. It wasn’t just being pushed in; it was pulling itself in.

“Oh god!” Olivia screamed as Dr. Hall began to thrust inside her. It stretched her, filling her completely. Inside, she could feel it squirming with each thrust. It was revolting, sickening, disgusting. It was ecstasy.

Olivia wrapped her legs around Dr. Hall. She should be pushing her away, but instead she was pulling her closer. The creature seemed to hook into Olivia’s flesh, the scales acting like ridges designed to stimulate every nerve ending. Every thrust sent waves of bliss crashing through Olivia’s brain.

“I can feel her,” Dr. Hall moaned, her eyes locked on Olivia’s. “She’s almost ready. She’s going to give you a gift.”

The thing inside Olivia pulsed. Olivia began to cum, shaking, as her pussy gripped the creature. She felt it swell, felt a pressure deep inside, and then a sensation not unlike the feeling of a man cumming inside her, but so much more powerful. It didn’t feel like liquid. It was solid, gelatinous. She felt it, something released, wiggling its way inside, past her cervix.

Dr. Hall was cumming too, shaking, gripping Olivia’s hips tight. “It’s viviparous,” she said between her moans. “Live young.” It was invasive, terrifying, and the most intensely erotic thing Olivia had ever felt. She was still cumming, her orgasm intensifying when it should have been ending.

“Oh God, oh god! It’s so good!” she screamed, the fear completely gone and replaced with nothing but pure rapture. A sudden, sharp clarity came over her. Why had she felt revulsion, she wondered, when the thing Dr. Hall had given her was so beautiful?

When the waves of pleasure finally receded, the room was quiet. Dr. Hall lifted herself off her student. The parasite retracted with a wet, sucking sound, withdrawing back into her body, hiding itself away until only her normal labia remained.

Olivia’s breathing slowed, a feeling of contentment coming over her. She felt full. Not just full physically, but full of life, full of purpose in a way she’d never been before. “How… long?” she asked.

“Not long. A few months,” the doctor replied. “Reptiles are ectothermic, of course. They can grow remarkably fast given the right circumstances, and your body temperature is quite warm.”
Dr. Hall smoothed her hair. “It should reach sexual maturity in three months. If yours is female, like mine, you’ll need to mate with someone carrying a male host to get it pregnant. A couple of the girls that went with me have one, don’t worry.”

She leaned down, running a finger along Olivia’s jaw. “And if you have a male, well, you’ll need to spread its seed to women who have a female. With time, perhaps you’ll be fucking me,” she grinned.

Olivia nodded and put her clothes back on, her movements now completely calm. She looked at the stack of papers she’d been grading on her desk. It all seemed so trivial now, so unimportant compared to her new purpose. She pushed the papers aside.

“Dr. Hall?”

“Yes, Olivia?”

“The population size,” Olivia said, her voice steady. “We need to increase the population to ensure genetic diversity. I know a few candidates in the department who would be… compatible.”

Dr. Hall smiled, a predatory expression. “Why don’t you come by the reptilarium this evening? I’m having a meeting with some of the other students that went with me on the trip to Brazil. We can discuss your fieldwork proposals there.”

Olivia smiled.

END