Fallout Behemoth Blight

WARNING THIS STORY CONTAINS: Female to Male, Strongfat Mutant Behemoth (Fallout) TF

WORDS: 4000

An expedition into a vault goes awry as three women are transformed into bulky, testosterone fueled mutant behemoths with a need to take care of the urges springing from the bulges between their legs.

This story was for an anonymous commissioner.

Commission Info: https://href.li/?http://eyebeast.deviantart.com/journal/Commission-Info-615442807

----------------------------------------------------------------------------------------------------------------

            Fidgeting with her chin-length, black hair, Hannah paced back and forth to try and get rid of her stress. This was done under the guise of following standard survival technique of watching the wasteland for any sign of danger. That didn’t prevent the scientist from repeatedly glancing back at the massive vault door before her marked with E001. It was the very reason the usually meek scientist had wandered out from the safety of her lab.

            Standing next to a control panel connected to the fortified entrance was a woman in a vault suit bearing the numbers 52. Eyeing up the woman known as Laney’s ponytail of blonde hair and the laser rifle strapped to her back, Hannah was grateful that she had an experienced vault dweller on hand for the exploration. Though the blonde woman had given the instruction to let her focus on her task, the scientist couldn’t stop herself from staring with great interest about every step of the vault opening process.

            Before Hannah could make any further observations, her view was blocked by a woman with tanned skin adorned in a set of black leather armor. Daring to move her gaze upwards, the scientist shuddered as she met the angry glare of the former raider turned mercenary for hire known as Viscera. The scientist only managed to take a brief look at the woman’s head of buzz cut, red hair before a snarl sent her retreating backwards for fear of being on the receiving end of a sawed-off shotgun.

            “Woah, where do you think you’re going?” asked a familiar voice.

            Turning herself around, Hannah found her fellow scientist, Derrick. Standing a foot taller than her, she had to tilt up her head to see his head of short, brown hair and his always comforting face. His thin-framed glasses worked alongside his neatly groomed beard to undo some of the stress that had been plaguing her ever since she left her shelter. Any ease his presence could muster for her was undone by the splotches of green goo spread across his coat from when they had run into a swarm of bloatflies earlier in the expedition.

            “We shouldn’t have come here,” Hannah said, trying and failing to walk off when Derrick grasped her shoulder.

            “We’ve already come so far though,” Derrick commented. “Aren’t you excited about finding what’s in the vault? It’s apparently one of the facilities designed by an offshoot division of Vault-Tec. Who knows what kind of strange and wonderous inventions they’ve come up with.”

            “Not like it matters,” Hannah replied, giving up and turning around to talk to him. “Even with Laney’s Pip-Boy, it is highly unlikely that we’ll be able to open-“

            Hannah’s doubts became overshadowed by the sound of metal starting to shift. Turning back towards the door, she watched as it rolled aside to reveal a dimly lit corridor that led into the depths of the earth. Taking a step forward and peeking her head into the ominous passage, Laney turned back around to show off a prideful smile.

            “Sorry for the wait,” the former vault dweller called out. “They weren’t kidding when they said it was made by a different group of programmers. Thankfully, the control panel still has the same backdoors as any other Vault-tec computers.”

            “Any idea what we’re running into?” Viscera asked, double-checking her shotgun’s ammo.

            “Not a clue,” Laney replied, gesturing for the group to follow her inside as she pulled out her laser rifle. “But I’m hoping to finally find a vault that’s not too crazy. When this is over, I might turn it into my new home.”

            “How likely is that?” Hannah called out.

            “Slim unfortunately,” Laney answered. “I’ve been looking for a while and each time the vaults come with some weird experiment or have been taken over by unfriendly tenants. Still, can’t help craving the easy life.”

            Viscera let out a huff. “You want to waste all of the skills you learned up here just to sit in a hole in the ground?”

            “A life of boring comfort is more than enough for me,” Laney replied. “Besides, you got a taste of easy living yourself with those Vault-Tec undergarments I gave you.”

            “They are… quite comfortable,” Hannah was forced to admit.

            “And functional,” Laney added, bringing up memories of her detailed explanations of the garments ability to stretch to any shape or form.

            “Regardless of if this is the vault you’ve been looking for,” Derrick began as the group headed deeper into the vault, “my lab will be more than happy to provide enough caps to keep you comfortable for quite a while. Same goes for you Ms. Viscera.”

            “Yeah, yeah,” the mercenary replied, waving about her gun to ensure nothing would get the drop on them. “What are you going to do with the research anyway?”

            “We’re not entirely sure, to be honest,” Hannah admitted. “But every vault our lab has discovered thus far has been able to provide knowledge that has proven to be quite valuable to our benefactors.”

            “Yeah and who would that be?”

            “You don’t know them? They’re the-“

            Hannah’s explanation turned into a scream as the ground beneath her feet seemingly disappeared. Plunging down a dark chute, she frantically looked around for the rest of her team. While she did see Laney and Viscera sliding alongside her, there was no sign of Derrick. Holding onto the hope that he would rescue them if they managed to live through whatever came next, she braced herself as she was momentarily blinded by a bright light.

            Landing upon a collection of cushions, Hannah and the other girls looked around the sealed off room. Working on instinct, Viscera moved over to the door panel and tried to unlock it by blasting it with a few rounds of buckshot. All that succeeded in doing was making the room ring and waste the mercenary’s ammo. As the group’s hearing recovered from the failed escape attempt, they eventually noticed the thing watching them from a nearby window.

            “Quite a rowdy group of test subjects,” commented the Robobrain, flexing its pincers as the group stared at the human brain contained within the glass globe atop its body. “It should make for some fascinating results. Please stand by while I administer the modified FEV virus.”

            “Let us out, you walking tin can,” Viscera shouted out as she banged on the door. “When we get out of here, I’m going to rip that brain out of you and shove it up a Deahclaw’s-“

            Viscera’s aggressive escape attempt came to a halt as she was subjected to a strange, green gas that began to drift into the chamber. Overtaken by a series of vigorous shuddering, she ended up falling to the floor. Gritting her teeth as she tried to keep herself steady, she looked towards her companions for help. Unfortunately, her attempt to speak devolved into a series of grunts as a shade of dark green appeared along her skin and a pair of tusks jutted out of her mouth.

            “No,” Hannah said, watching the mercenary convulse on the floor. “This can’t be happening.”

            “Everything will be okay,” Laney said, putting a comforting hand on the scientist’s shoulder as her eyes scanned the room for an escape route. “I’ve been through worse before. As long as we keep her heads together we’ll be able to-“

            Once more, a puff of the green gas spouted out from an unseen vent to stop Laney in her tracks. Dropping her laser rifle, the former vault dweller succumbed to the same phenomenon as she fell to the floor. The green coloring of her skin was shown off as her suit began to tear from her swelling muscles. As she gained her own set of tusks, she let out a primal growl just as her foot smashed her weapon to pieces.

            Too busy gawking at her companions’ transformations, Hannah had no chance to defend herself from another puff of the gas. Having learned from experience, she tried to protect herself by clutching her throat and trying to cough out the tainted air. While she was considering vomiting out the gas, her legs gave out on her to send her tumbling to the ground like the others.

            Writing on the floor, Hannah fought against her panic instincts in an effort to figure out some way to save themselves. That task became even harder as she watched her coat tear at the seams thanks to her swelling, green muscles. Shaking back and forth across the floor in an attempt to will away her transformation, she ended up getting blinded by the overhead lights.

            When Hannah’s vision returned moments later, her sight fell on Viscera. The already imposing mercenary got to show off her increasing bulk as it began to tear apart her armor. In the wake of the leather being ripped to shreds, the scientist managed to see the woman’s breasts start to be overtaken by a pair of swelling pecs. However, the odd nature of Viscera’s bulged out, green chest became secondary to the bulbous gut she developed.

            Viscera’s protrusion hoisted her off the floor and allowed Hannah to see the bushels of red hairs lining the belly button. Following the trail downwards, she managed to notice something poking its way out from beneath the gut. Had she not been dealing with her own changes; the scientist would have liked nothing more than to indulge her curiosity about the large bulge stretching out the mercenary’s Vault-tec brand undergarments.

            The sound of clothes being ripped apart made Hannah instinctively look at her own body. While her coat was straining to keep her muscles in check, the source of the tearing noise came from Laney. At that moment, the former vault dweller was having to contend with her own bulky biceps and a barrel-like gut. Though she shared some of the scientist’s fear at first, her green face changed into an expression of simplistic glee once she too developed a sizable growth between her legs.

            Letting her jaw hang open and brandishing her tusks, Laney showed no shame in letting her clawed fingers slide across her exposed muscles. With a toothy grin, she squeezed the muscles of her thickened thighs to relish in their mass. Husky laughs continued to echo from her throat as she was given a chance to grope at the hefty, green mounds that were her ass cheeks. Giving her bulge a good squeeze, she let out a pleased grunt before trailing her fingertips up her own trail of blonde body hair.

            Just as Hannah felt like she was about to hit the limit of what her mind could take, a surge of testosterone brought about by her muscles helped to deaden her thoughts. Driven by this primal instinct, she helped her growing form by tearing apart her outfit with her bare hands. Shredding apart the lab coat she had once held so dear allowed her to gaze at her own swollen pecs and thick limbs. Her powerful, rugged fingers moved on to pinching at the heft of her wobbling rear and grazing the black follicles spread across her massive gut.

            Letting out a series of guttural laughs to tickle her tusks, Hannah reached beneath her gut. In place of her womanhood, she felt a sizable bulge that tested the limits of the stretchable, blue panties wrapped around her wide hips. Rather than remove the restrictive garment, she found a strange sense of satisfaction in rubbing her cock within the confines of the fabric. She would have liked nothing more than to continue admiring her girthy, green form, but her attention was driven elsewhere as her head bumped up against the ceiling.

            “It appears that you three are taking well to the modified FEV virus,” the Robobrain commented. “It takes inspiration from these mythological creatures called orcs to modify the standard super mutant creation process.” With the press of a button, it made a part of the wall open up into a long corridor. “Please proceed forward unless you wish to be trapped in here. There is still a bit more growing for you to do, so we must move you to a new enclosure. You will find the next stage of the experiment there.”

            “Why do we have to go?” Laney demanded in a deep husky voice.

            “Yeah, you’re not the boss of us,” Viscera similarly growled, banging his fist up against the glass.

            “Now, now, no need to be so aggressive. At least, not yet,” the Robobrain commented. “If it makes things go smoother, I will say that you’re going to find a fun toy to play with in the other room.”

            “What kind of toy?” Hannah asked, surprising himself with the deepness of his new voice.

            “That’s a surprise that you’ll have to find out for yourselves,” the Robobrain said, sending the mutants running off down the corridor.

            Each heavy footfall of the mutant men served to help their bulky form shake off what remained of their clothes. With nothing in their way, their figures were able to further grow outwards and upwards. True to the Robobrain’s warnings, the tops of their heads were getting dangerously close to the top of the ceiling just as they spotted a bright light at the end of the tunnel.

            The trio of monstrous brutes walked out into what appeared to be a metal floored, fighting arena that was reminiscent of the Roman coliseum. When their vision adjusted to the bright, overhead lights, they were able to see that, while there weren’t any actual audience members, there were numerous cameras focused in on them. The multiple lenses reflected back to them the severity of their makeovers.

            Turning his head downwards, Hannah was able to take in the full bulk of his new form. Over the course of his trek through the tunnel, his already sizable figure had continued to gain in height in weight. Though his memory was a bit fuzzy thanks to a surge of testosterone, he could recall reading about a type of super mutant known as a behemoth that perfectly fit their horrifying visages.

            Focusing on his fellow mutants, Hannah was able to size them up while they were busy playing around with their figures. Despite the aggression he had shown earlier, Viscera was the shortest of the trio at a measly twenty feet in height. Laney stood about five feet taller, giving him the chance to easily grab onto Viscera’s sides and play around with his gut. Coming in at the thirty foot mark left Hannah as the largest; this allowed him to be the first to notice the door on the other side of the arena start to open.

            Eventually the sound of metal shifting aside to open up a passage garnered the attention of the three giants. Brushing back his unkempt hair, Hannah narrowed his focus on the miniscule man stumbling out from the darkness. Needing time to adjust to the light, Derrick seemed momentarily unaware of the three mutants. This gave Hannah a chance to take note of the various scrapes and bruises he had gained on his coat over the course of his time in the vault.

            Derrick signaled the return of his vision by letting out a terrified yell. The scream went against Hannah’s typical image of what he considered to be a once strong and courageous ally. Then again, he couldn’t really blame him considering he was looking at a group of monstrous behemoths. Nor did he fault the small scientist for letting out another panicked cry when Laney and Viscera started stomping towards him.

            “Let me out!” Derrick shouted, banging his fist up against the metal door blocking off his escape route.

            “That would ruin the purpose of the experiment,” the Robobrain spoke over the intercom, its voice barely audible over the mutant’s heavy footfalls. “We must see how the new mutants decide to mutilate and/or murder you.”

            “Please, open the door,” Derrick yelled, tears welling up in his eyes. “I don’t want to die! I still have so much science left to-“

            Another scream echoed through the arena as Derrick was grasped by Viscera’s fingers. Bringing him up to his face, the behemoth let out a snort to blow back the human’s hair. Licking his lips, Viscera opened up his maw to show off the frightening combination of his fangs and tusks. Moments before the mutant could make a meal of the scientist, he was snatched right out of his green fingertips.

            “What the hell are you doing?” Viscera called out towards Laney.

            “It’s mine,” Laney replied, holding Derrick close against his chest, smothering the human’s face with body hair in the process. “I should get the first taste of this human. I need to grow big and strong.”

            “You’re already big enough,” Viscera said, giving Laney a slap to the gut that nearly sent Derrick tumbling to the ground. “Give it to someone who needs the extra bulk.”

            “We could share him,” Laney suggested, holding up the shivering scientist. “You take the legs. I’ll take the head. We pull and eat whichever bits we get. Sound good?”

            Tapping a finger against his chin, Viscera eventually nodded. “Hmm, alright. I’m too hungry to argue anyway. Let’s do it.”

            “W-wait, hold on,” Derrick said as the mutants got in position. “You can speak. Surely that means you can listen to reason?”

             “Yeah, that’s why we’re splitting you, puny human,” Laney said, keeping a tight grip on his arms.

“Don’t worry,” Viscera added, grasping his legs. “It’ll hurt a lot, but only for a minute. Then you’ll be in our bellies.”

            Watching the other mutants prepare to rip Derrick in half, Hannah’s logical side managed to peak through his modified mind’s instincts. Pushing back the need to devour his co-worker, he tried to come up with a way to save the human. Seeing Viscera and Laney start to gently tug on his limbs, the behemoth let his instincts take over.

            Charging forward at full speed, Hannah made his way towards the group. If the sound of his stomps weren’t enough to get their attention, he made sure with a deep roar that seemed to make the room shake with its pure volume. The sound was enough to freeze the other mutants in their tracks to look on in fear at the towering monster. Using this to his advantage, Hannah took the opportunity to easily pry Derrick from their fingertips to claim him as his own.

            “Please, please, don’t eat me,” Derrick said as he held up to Hannah’s face. “At least give me a chance to find out what happened to my…”

            Derrick paused for a moment as his eyes traced over the unkempt, black locks surrounding Hannah’s cheeks. Glancing down at the mutant’s torso, he could see scant traces of the behemoth’s lab coat wedged between his green pecs and belly. Dragging his eyes back up, he stared into her eyes and slowly pieced everything together.

“Hannah,” Derrick began, “is that you?”

            “Hey!” Laney called out, reaching for Derrick only to have him held just out of reach. “Give him back.”

            “Yeah, he’s small but we can still snack on him together,” Viscera added, her attempts to claim the doll-like Derrick equally unsuccessful.

            Hannah let out a snort. “You’re stupid. Human isn’t for eating.”

            The other mutants scratched their heads.

            “Then what is he for?” Laney asked.

            “He’s for… for…”

            Hannah’s intellect failed him under the duress of his modified figure. Looking down at his human, his immediate thoughts didn’t help with images of how good Derrick would taste. Suppressing his hunger left him to focus on another desire of his. One that brought a toothy grin to his face as he felt the warmth coming from between his legs.

            Rather than say another word, Hannah proceeded to rub Derrick into the hairy bushels of his armpits. Once the human was thoroughly acquainted with the fragrant follicles, he moved on to pressing the human into his gut as a sort of massager. Bringing Derrick over to his backside, he found sick glee in getting to introduce him to the thin piece of fabric wedged between his ass cheeks. The feeling of the small fingers rubbing up against the stretched out undergarments gave Hannah the final push to move towards his true goal.

            Any sense of relief Derrick felt as he was freed from the gigantic ass was undone as he was placed just below Hannah’s gut. Pressed up against the sizable bulge between the mutant’s legs, he was dragged back and forth across its girth. Gritting his teeth from the simple pleasure of feeling his former superior shudder against his cock, Hannah turned back towards the awestruck mutants.

            “That looks fun,” Viscera said.

            “Can we try?” Laney asked.

            “Sure,” Hannah said, holding out Derrick, only to stop a few feet short of passing him over. “If you break him, I’ll break you,” he threatened before finally allowing the others to have his toy.

            “Wow, look at this,” Viscera commented as he held the human up against his cock. “Mine’s nearly as big as he is.”

            “Same,” Laney replied once he got a turn to compare Derrick’s form to his bulge. Tired of smothering the human against the throbbing tip, he moved on to giving Derrick a close up look at his hairy, bugled out pecs.

            “Give him here,” Viscera said, taking Derrick to have a turn of squishing him in-between his girthy, green butt cheeks.

            “Okay, that’s enough,” Hannah replied, snatching back his human. “My turn again.”

            “Hmm, how peculiar,” the Robobrain commented as it watched Hannah cover Derrick in the musk of his gigantic cock. “Most other test subjects would have ripped their human apart by now. Thank goodness. I was getting tired of having to clean up the mess.”

            “What brain robot do with us now?” Laney called out.

            “Hmm, I suppose you are in need of further observation,” the Robobrain relented. “I’ll go and fetch you some non-living food for now. I’ll be back shortly.”

            “What do we do until then?” Viscera called out.

            Holding Derrick up to his face, Hannah was pleased to see an almost drunken, yet pleasurable face on the scientist he used to look up to so much. “Keep playing with our new toy,” he replied before shoving Derrick back between his girthy, green legs.