Jeff felt his dick harden as his his horny mind thought of the possibilities. Jeff then heard his mother, Jennifer call him to let him know that their neighbor Gabriel is downstairs currently. Upon hearing this a perverted idea crossed Jeff's mind, he looked at the chronivac and saw that his mother, his older sister Abby and their neighbor Gabriel where currently standing near each other talking. Jeff selected all three and began his horny plan.
Using the chronivac Jeff made these changes to them: Gabriel, Jennifer, and Abby will be fully aware of all changes to them, everyone else except Jeff won't be,
all changes will take atleast 2 minutes to complete,
all changes will be extremely pleasurable, and now unto the fun parts.
Gabriel, Jennifer, and Abby will merge but keep their heads separate, Gabriel's head will be in the center and have full control of the body, Abby's head will be on the right and can be given control by Gabriel, and Jennifer's head will be on the left and she can be given control by Gabriel,
They will be female and have no male genitalia,
Their lower half will turn into a large spider, making them a spider-taur,
They will lust after their new body,
Abby and Jennifer will do what they can to make Gabriel horny and masturbate so that they can all feel the pleasure their new body gives them,
Abby and Jennifer will be in love with Gabriel,
They will have three pussies on their rear half and a pussy-mouth on the front,
They will have 4 H-cup breasts that a very sensitive and have super stretchable and fuckable nipples,
Their front pussy will have tentacles coming out of it for dragging in females into their womb for digestion, men can't be dragged in,
When they digest a female, Abby and Jennifer can distribute the mass to make them look sexier,
Their heads will all look the same,
They can change their appearance between looking like a red haired MILF or a purple haired curvy teenager,
They will have 8 arms, and 12 legs,
The feet of their legs will become high heels,
Jeff's father Brent will see the merged creature as his wife, while Jeff's little sister will see them as her mother,
Gabriel, Jennifer, and Abby will recognize themselves as sex monster and want to grow bigger, sexier, more monstrous, and more powerful and commanding.
Now for the last few touches the sex monster will never be able to gain any male genitals, even if they use the chronivac,
They will have a high libido,
Everyone in the house is okay with being seen naked by family members and having sex with other family members,
And lastly they will allow both Brent and Jeff to fuck her.
With that done Jeff hit enter and saw his clothes leave his body and reappear in his closet, Jeff smiled at this and got up to head downstairs to see his targets merge into a sex monster. Jeff passed by his naked father on his way downstairs. Jeff got to the living room and saw the three targets with his sister nearby. Jeff saw Abby's body bump shoulder to shoulder with Gabriel on his right side, while he saw Jennifer's line up on his left. Jeff watched with his hard on, on full display as Gabriel, Jennifer, and Abby began to melt into one another, and Abby's breast went below his mother's as their bodies became one.
Jeff noticed his little sister completely oblivious, to the changes happening in front of her, which made Jeff even harder as he was the only one, except the three who were merging, who gets to witness the birth of his sex monster mother. Jeff continue to watch as their torso extended to accommodate the 4 growing boobs and 8 arms, he saw as their body became more MILF like, their faces becoming impossible to tell apart as they now looked that of a mature sexy women, with scarlet red hair that reached her ass. Speaking of ass Jeff saw it expand intill it was that of a human sized spider abdomen. Jeff saw this, all the while hearing their moans change from their different pitches intill they were the exact same, the pitch of a motherly women in heat.
Jeff witness them grow 12 legs and the ends of the legs turn into 2 inch high heels all still covered in their spider chitin. Jeff started to Jack off to their transformation infront of them fully aware that they are aware of their changes. Jeff saw as they bit their lips and using their arms began to play with themselves no longer able to hold back. The last changes to them he saw was, as they were playing with themselves they reached down with their lower hands to play with their pussy and saw as it grew bigger and opened wide as tentacles came out of it as they reached climax.
Jeff came soon after cumming at the feet of his new sex monster mother. Jeff looked around the living room and noticed that the whole room change to better accommodate his new mother and that all the pictures have been changed to show that she has always been like that. Jeff heard his father enter the living room, his dick nice and hard ready to fuck his wife.
Jeff saw Gabriel launch herself at Brent and embrace him in what looked like a hug, but Jeff realized that his how she as sex with her front pussy. Jeff saw his 6 feet father's head get smothered in the middle of Gabriel's four H-cup breasts, and a pair of legs wrap itself around his waist as he began thrusting into her while standing. Jeff then saw Gabriel lift her abdomen revealing her three wet pussies on the under side of her arachnid ass, and saw Abby's head turn towards him giving a naughty wink. Jeff knew what his mother wanted now, but as soon as he was inline behind her, she shoot a string of web at him. With the web string attached to his chest, Jeff felt his mother pull him the small distance between them.
Jeff saw his mother them break the sting from his chest using her rearmost feet and tie his hands to her spider ass and tied his hips to her as well. Jeff didn't know why she did it but quickly found out as she leaned forward dipping his father to the ground and lifting him up high enough that his feet didn't touch the ground. Jeff now in the air decided to give the sex monster he created what she wanted, and began to thrust his average dick into her central pussy. Jeff heard all three heads moan in delight at his thrusting. After a few minutes they all reached their climax, with Gabriel orgasming like crazy.
Gabriel disentangle everyone from her. As soon as Jeff was down he realized that his younger sister was masturbating as she watched them fuck. Jeff saw Gabriel make her way into the kitchen to make lunch, while his father sat on the couch to recover.
Jeff made his way back up stair think what should he do with the Chronivac now.......
I would like it if people continue this, since I'm only good at making set ups for other people to continue off of.