(rewrite)
A/n - Thanks to TheNoekk for the idea. Now, when I hear "alien abduction" the first thing I think of is The Sims 4, and in that game, it's human males that can be impregnated by aliens, so, at first I considered this might be the time to play around with MPreg. However, I scrapped that idea. I don't want to touch that topic unless I have a good idea where the baby could grow within the male body and how it could be safely birthed. Besides, the description of this story does say "where Marinette gets pregnant". I'm ambivalent to the idea, so let's have a poll. Should I try writing an MPreg at some point to switch things up?
Unbeknownst to all who lived their, a research vessel flitted through the skies of Paris, its cloaking devices turning it invisible against the sky. It hailed from the distant planet of *#] on a mission to study life on earth. They had so far determined humans to be the dominant race on the planet and were now interested in watching one grow up in the wild. Of course, the younger the specimen the better, but humans were remarkably protective of their offspring. They would have to tranquilize the adults in order to get anywhere near the child, and if they were going to all that effort, they might as well trace a child from the earliest moment possible - their conception. Human females, they discovered fairly easily, carried their offspring inside of their body for a short while before defecating the child and continuing to raise it out side of her body. It stumped them for several months, however, how the child got inside of it's mother in the first place.
Due to humans apparent reluctance to perform the act in public, it took some time for the researchers to discover, but carefully placed cameras in human dens revealed a strange ritual where two individuals shed their pelts and pressed their bodies against each other. Careful analysis of data revealed many females found later to be carrying offspring had been observed performing that peculiar ritual with male. A notable number of the offspring also shared physical resemblance with the same males that were observed with the mothers. That further supported the hypothesis, humans were a species that procreated by combining genetic information from two individuals of opposite gender, and that ritual must be the key to it.
The researchers wanted to know more, but humans were difficult subjects. Luckily, they appeared not to be the only species that reproduced in like manner. Many of earth's animals seemed to follow a similar pattern and were far less abashed about mating in public. The researchers picked up a pair of rabbits, who voluntarily demonstrated how they furthered their species. The male grew a mysterious appendage which he plugged into the female, and when he withdrew, there was a white fluid inside of her that wasn't there before. Sure enough, the female rabbit had kits a month later, was the male's white fluid responsible for putting the baby there? It was time to return to humans.
For this, they needed a pair that were easy to track, one that could be reliably found at the same place at the same time. They found them. A male and female ran across the rooftops every night after most humans had returned to their dens. They were young, younger than most the researchers had observed rearing children, but their bodies appeared to be sexually mature, and at times they displayed unmistakable courtship behavior. Command readily approved the two as test subjects, they would do nicely.
The last thing Adrien remembered, he'd been Chat Noir. He and Ladybug were standing on a rooftop scanning the night sky, then he felt a sting something like an insect bite and he passed out. When he woke up again, he was chained to a table in a weird light colored room. The next thing he noticed was the people around him, at least, he thought they probably qualified to be called people. The shape of their bodies was something he had never imagined and couldn't begin to describe. One came forward, extending what could best be described as its eyes so that it could examine him from up close. the same appendage then unexpectedly grabbed at his skin, feeling him from the top of his head to the bottoms of his feet. When the creature trailed its one appendage over his private parts his penis involuntarily jerked, drawing the alien's attention to it. The alien began more thoroughly investigating what it thought to be a fifth leg, except this one had a hole in it, and the female counterpart did not have one. The more it was touched the harder this appendage got until a small amount of liquid began to come out its tip. That made the aliens wonder, could they get the male to release that white liquid without putting it straight in the female?
They put a sterile bucket under his penis, they didn't want to lose anything that came out of it, this could be valuable for study! They continued to stimulate him until with a loud grunt he released a stream of the white liquid into the bucket. Excited, the researchers rushed the fluid off to their lab, chattering among themselves.
As the aliens moved away from him, he had more opportunity to look around the room. There, strapped to a table on the opposite side of the room, was Marinette. She was there watching him, but hadn't said a word, wasn't that odd? He tried to call out to her but nothing came out of his mouth. He'd just heard himself make noise moments before when he came, but apparently he could only do so involuntarily. Marinette must be in the same state.
Marinette felt a small amount of relief when Adrien finally noticed her. She was a little embarrassed for him to see her, naked as she was, but he was the only friendly being in the vicinity and she wanted to make contact with him. She'd tried calling out to him as soon as she'd seen him, but her voice was weak, she couldn't even hear it herself. He hadn't looked around much while the aliens were touching him, closing his eyes and most likely trying not to be aroused by their research. When their captors were finished and disappeared into a different part of the ship, he looked right at her and mouthed two syllables. Was that 'Mari'?
'Adrien,' she tried to respond, 'do you know where we are?'
He shook his head, either saying, no, he didn't know where they were, or that he couldn't read her lips and didn't know what she'd just said. They tried to communicate for a few more minutes, only to give up when the aliens came back into the room. This time they approached Marinette, prodding all over her body, paying special attention to her breasts and crotch, which they seemed to realize were the parts of her body most different from Adrien's. Both of them felt a nervous rush as they recognized the vile of Adrien's semen being brought over to Marinette. One filled a syringe with the semen while another poked an unfamiliar device into Marinette's vaginal opening. Still more wheeled in a monitor showing live video footage of an alien poking at the camera. It only took moments to realize that the camera was that same device that had just been inserted into Marinette. Next, the tip of the syringe was fitted inside of Marinette. The footage went momentarily dark as its light source was cut off, then brightened again as a light built in to the camera apparently illuminated her vagina from the inside. With a click, some sort of pistol was fitted to the opposite end of the syringe. Marinette felt her heartrate increase, sensing what was about to happen to her.
From across the room, Adrien watched the alien researcher pull the trigger. Marinette's eyes widened as far as possible and she opened her mouth in a silent scream. She didn't appear to be hurt, just stunned, which was much how Adrien felt himself. His eyes were drawn away from her face by the images on the monitor. He could see his own cum hit the back of her womb, where it began to drip down and out of her body. Then the camera began to zoom. It zoomed in so that the intrances to her fallopian tubes looked like giant looming caverns. It zoomed until he could make out the shapes of individual sperm swimming in his semen. Many of them quit wriggling and died within minutes, but there were yet hundreds. Some swam in circles or in the opposite direction of the rest, but most struggled their way into one fallopian tube, the one that no doubt emitted chemical signals of a mature egg. It appalled him how stupid many of his sperm were. Sure, they didn't have brains, but they only had one job, and still dozens turned asside and tried to burrow into her uterine wall. But, it wasn't any of those incompetent sperms that were going to make a baby. If Marinette was getting pregnant that day, it would be by the single strongest and fastest sperm that had been pumped into her that day out of millions. Seeing how valiantly the sperm struggled in their quest, there was a certain impulse to cheer them on, though they still weren't sure how they would feel were it actually a success. By the time the egg came into sight, the number of sperm had thinned out to the point where they were countable. Twenty, maybe thirty, made contact with the egg and tried to burrow inside. After a while, one dissapeared completely inside and all the others simultaneously stopped moving. The egg had locked them out. At that moment a new life had begun, but the pregnancy wasn't official yet. The zygote still had to make its journey down into the womb and implant there for any chance at survival. If it couldn't do that, life was over as soon as it started.
The alien researchers kept their specimens for monitoring overnight. They'd hoped to see the pregnancy stabilized before their release, but the whole process was happening slower than anticipated. At this rate, it looked like it could be days before the baby began to grow in earnest. The specimens were probably starting to get hungry as well, it was best to release them so they could go find food. It wouldn't do for their research subject to lose the baby due to being undernourished.
Having fallen asleep on the research vessel, Adrien and Marinette reawakened on the very same rooftop as where they'd been taken. They were laying on their backs, their clothes laid carefully on top of them. The aliens had been unable to figure out how to put their clothes back on them the way they had them before, but they realized that covering up in public was important to humans and did their best to respect that. As soon as they were alert enough to do so, the two rushed to dress themselves, blushing as they did so. Marinette smiled shyly at Adrien, her hand lingering somewhere over her belly.
"So, how long do you think we've been gone?" he asked her. They needed to start discussing this somehow, but it was tough to know where to start.
"It's light out," she noted. "It was at least overnight, but it sure felt longer."
They would soon learn that they'd been gone for 32 hours. The sun had just set at the time they were kidnapped. One full day had passed while they were being experimented on, then they'd been kept until daylight before being released. Having been kidnapped as their alter egos, the two were finally able to put two and two together about each other's identity, especially since they had to transform to get off the roof. Once the police discovered the missing teenagers to be alive and heard their story, they were compelled to be seen by a doctor. They were found to be unharmed, save for the fact that the entrance to Marinette's womb had been blocked off by a seal of unknown substance. It didn't appear to be harming her, and appeared impossible to remove save by surgery, so it was decided to leave it alone for the time being and see what happened. The plug was considered to be non-organic and some sort of alien technology, most likely there to deter her from removing the camera from her body.
The aliens kept watch on their cameras with bated breath, through study of other earth mammals, they had some concept of a pregnancy not taking. As a zygote traveled down the fallopian tube it's single cell divided and it became a blastocyst. When the blastocyst reached the uterus, there had to be enough uterine membrane for it to successfully anchor. Only then would the mother's body be triggered to raise the production of progesterone, effectively starting the pregnancy. They had confirmed their subjects had sufficient lining for implantation, but that wasn't necessarily a given. If the mother's body sensed the blastocyst to be nonviable, it would flush out the lining and force the blastocyst out of the body. The plug inserted in the female's uterus was programmed to open under such circumstances - forcibly keeping detached lining in her for too long could be harmful to the female's health, and they wouldn't gain much by researching a baby that was doomed to die well before it could ever be born. If that were to happen, all they could hope to do was either recapture the pair to breed them again, or wait for the female to mate on her own terms. Curiously, though, many humans appeared to hold off on mating well past the point they were physically capable of it. If they wated for her to do it on her own, it could be years.
Luckily, the blastocyst did implant. It appeared humans were simply slower at the process than smaller mammals. Like any good researchers, the aliens had planted tracking devices on both specimens and were able to follow them by arial drone through their daily lives. Even though no change were visible from the outside, the female seemed to know it when she was pregnant. The moment her baby was settled into the spot where it was to grow, she placed her hand over her belly with a contented smile.
There were changes in the male's behavior as well. Though he still parted ways with her at night, he spent more time with her during the day than he ever had before. Sensors installed in his tracking device monitored his vitals, and reported spikes in his blood pressure any time she was around an unfamiliar male. Knowing that they had a child on the way held extreme power over the minds of both subjects.
The female, they noted, modified her diet. Humans were able to eat an absurd range of foods; and this one had been observed to have a varied diet prior to her pregnancy. They had observed before that females with child were usually more choosy about what they ate, and this one followed suit. They couldn't for the life of them figure out why. A few researchers came up with various hypotheses, but they weren't able to prove any of them. Did pregnancy alter the mother's senses so certain foods became unappealing? Were some of the foods adults could eat toxic to their young and the mothers somehow knew that? They would have to research this more at a later date.
Back on the intrauterine monitor, magic was happening. The nondescript blob of cells multiplying inside the egg burst free from the protien coat caging them in, in certain terms, the egg had hatched. From there the cells began to separate into distinct layers. The individual cells were dividing rapidly, doubling their mass roughly twelve times in a single day. Before too long, the researchers were forced to zoom out to keep the entire mass in their sights. By the time the sun had risen and set ten times there was a translucent yellow ball, not unlike a raw egg yolk. The body of the embryo grew parallel to it, curving around the sac. From there the structure elongated and folded in on itself until around the twentieth day a dark red spot appeared in the midsection. Lighter red rays led off of it in every direction, this was the baby's heart. At this point the embryo looked more like a fish or lizard than a human - it had what looked like a tail and even a dorsal fin! By the time the moon had completed a cycle, the part that they knew would become the baby's head was larger than the rest of it and flopping down over the body, directly over the area where slightly indentations suggested where arms would come in. Nerves too were establishing their connections through the body, the development of earth creatures was amazing!
Somewhere around the fortieth day the beginnings of legs appeared, followed soon by rudimentary eyes and ears. Months passed and over time the tale shortened, the baby grew skin, it was looking more and more like what they'd come to expect of a human. It had now become a fetus. It was small, stretched out, and more frail looking than a full term baby, but it was no longer hard to imagine how it would transform itself in the final months. The greatest mysteries had been solved.
The city was abuzz with news of the so-called alien baby. Both of the abducted teens claimed it was their biological child, that the only thing otherworldly about it was the circumstances of conception, but conspiracy theories still abounded. People speculated that the baby would have green skin, a balloon of a head, and tendril-like fingers. Skintone aside, it sounded like most of the predictions would come true if the baby happened to be born premature. A petition was put forward to have the birth on live television, and it gained enough traction for a local news network to make an offer on it. Adrien and Marinette, now engaged with the consent of their families, declined the offer, but agreed to introduce the baby publicly as soon as they were discharged from the hospital. There were still those who suggested that gave them time to switch out the baby, but the offer at least satisfied the masses. So, it was decided. They would show off their perfectly normal baby to the world, disappoint everyone who had hoped to see an alien, and fade back into normalcy with maybe a hunch but no proof that alien researchers were still watching their every move.