You are Y/n L/n and You are the son of A Scientist. A Robotics Scientist. A Recently Divorced Robotics Scientist. You're Father was A Kind, and Nerdy Man which you definitely Took after but your Mother was to put it simply A Total Bitch, and divorced your Father because he refused to Pay for her habits any longer!

You Never liked your Mother anyway and said Good riddance as it was easy for your father to gain custody of you because He actually made really good money, and Your Mother didn't want you either! Yet things do get really as your father is usually gone for Months without returning and you're all by your lonesome! Well... That is until today!

Dad: "Y/n, I want you to meet your new Robotic Little Sister! Penny!"

Penny: "Salutations, Brother Y/n!"

Y/n: "U-Um... Hello Penny... Um... How are you...?"

Penny: "My Diagnostics say Good."

Y/n: "Oh, Um that's good..."

Penny then puts up A Cute smile and winked!

Penny: "Good!"

Dad: "Well as You can Penny is A Real sweet Robot girl. Like Megaman or Astroboy!"

Y/n: "Dad, I have no Idea who Astroboy is?"

Dad: "Well you know what I mean. She can do everything you need. She can cook, Clean, Act As A Vent, A Pillow, Can Play any game you want, and she has A Combat Mode to Protect you from any Bullies!"

Y/n: "Dad, I don't have any Bullies!"

You did though but that will come back later!

Dad: "Whatever you say, son! Well, I better get Going to Tokyo! We're working with DARPA On A Robot That can Open Beer cans!"

Y/n/Penny: "..."

Dad: "Yeah, It's A Slow year for DARPA..."

He then soon Left and Penny looked at you with her Big Puppy dog eyes, and you were just nervous because you had no idea how to interact with her Since she was A Robot and You Just met her!

Y/n: "So, What do you wanna do?"

Penny: "Anything you want to do Big Brother Y/n!"

Y/n "Yeah, don't call me that... It's weird..."

Penny: "Okay, Big Brother."

Y/n: 'Heh, so cute. Wait, what Am I saying?'

So you then Took her to Play some Super Smash Bro's Ultimate where you were Using your Mian Kirby and Penny was Using Megaman because she feels like she can Relate to him and she was Kicking your butt Big time!

Y/n: "No, No, No, No! Gah!! Goddamnit!! How do you keep winning so easily?"

Penny: "Well Big Brother Y/n, It's Actually A Really easy game, to be Honest. It has Very few Variables, and constants to the equation of winning once you know what your Opponents are like and after A While I just got used to your fighting style."

Y/n: "Oh, I suppose that Makes sense."

Penny: "But then again you were Button Mashing like Crazy."

Y/n: "Okay, Smart Alec, Let's go another round."

Just then you heard A Loud grumbling sound, and you knew you weren't hungry so you Tried to see what it was when Penny tapped your shoulder turning to you!

Penny: "Big Brother Y/n, I seem to be Hungry."

Y/n: "Hungry!? I thought you were A Robot!?"

Penny: "Yes, I am but Father wanted me to be as Human as Possible so He gave me convert Bio Mass, into A Perpetual Fuel source for my Energy Core!"

Y/n: "Huh?"

Penny: "I can eat Foods, and Convert it into Pure energy, Like How A Human does it."

Y/n: "Oh Okay! So what do you like to eat?"

Penny: "Anything really. I was Just recently Built so I never ate anything before."

Y/n: "Oh, Your Poor thing! Let me make you some of my favorites! Ramen!"

You then Made some of the Best damn Ramen you ever made and handed it over to Penny and as soon as you turned around you quickly turned back around to see that Penny had already finished the entire thing, and was offering up her bowl for some more!

Penny: "That was Delicious, Big brother Y/n! May I have some more?"

Y/n: "Sure, Penny! You sure like to eat don't you?"

Penny: "Indeed! This is Some kind of Brand new Sensation to me and It's completely wonderful! I mean I never knew how good food is and now I want to try it all!"

Y/n: "Great!"

Sometime Later!

Penny had nearly eaten out the entire Fridge as she now nursing her Food Baby on the couch and you were Just stunned that she could eat so much, but then again you couldn't be surprised because she was some super-advanced Robot! 

You were Blushing thinking about Rubbing her belly because she seemed to be aching, and it would also be so soft and warm when Penny turned to you!

Penny: "Big Brother Y/n if you want to rub my belly, you can do it. I don't mind."

You then Blushed bright pink as you tried to look at Penny!

Y/n: "W-What do you mean by that?"

Penny: "Big Brother Y/n I can read you like A Book. It's not that hard. And Plus I don't mind at all."

You smiled and walked over and Began rubbing her belly and it was so soft, and warm, and it was like A Big Ol' Marshmallow, and you Loved it, And Penny smiled and Blushed at your touch!

Y/n: 'Man, She is so cute, and adorable, and she's chubby too! She's Perfect! Wait... What am I saying!? She's A Robot! An Android! I shouldn't fall for her! It's like falling in love with your Alexa! I just can't...'

Penny smiled thinking about what to do next!

Penny: 'So I can infer from this information that Big Brother Y/n Likes girls with A Much higher BMI. If I must earn that Love then I Must be of the highest BMI. Of course! That shall be My Goal!'

2 Months Later!

You were Now walking out of school when you were Greeted by Penny and you were Blushing when seeing her, as she was different than she was 2 months ago! Your father has come back yet, and thanks to your family's vast wealth you were able to fuel her eating habits which you were Happily willing to do, and now she was at the biggest she had ever been!

Penny: "Salutations, Big Brother Y/n! Should we get going home now?"

Y/n: "Y-Yeah, Penny, Let's Just go and- KYYAH!"

You were then Pulled Behind by your Bully who we'll just call Bully and he had already beaten you today For Your Lunch Money!

Bully: "Hey, What's this!?"

He then showed his Hand which was empty!

Y/n: "Um... Nothing..."

Bully: "Yeah, there should have been more Money but All I could buy was A Damn Sandwich!"

Y/n: "Look Dude, You see I was planning to use my allowance to take my Sister to this nice Buffet downtown and-"

Bully: "Why Don't my Fist take you downtown?"

Y/n: "No, No, No, I wouldn't like that at all!"

He was About to Punch you when Penny pulled you away from him, and she smushed your face into her Belly, as you began to calm down, feeling the softness, and warm comfortableness of her belly, as she began to protect you!

Penny: "How rude are you? Big Brother Y/n always warned me about People Like you! You don't even deserve to be in the same room as him! It makes me Gear's Grind, and Hydraulic Fuel Boil to see people like you hurt him so much!"

Y/n: "P-penny it's Okay, It's Just-"

Penny Just smushed your face back into her belly as she continued to rant!

Penny: "No It's not! I suggest you leave Now and Leave Big brother Y/n Alone, If you don't want to be Smashed around with such Force and Velocity, that Your Rib cage would splinter and shatter in such A Way that recovery would be incredibly Hard."

Bully: "Hahahahahaha! You think... Do you think you can Beat me up Girly? Wow, so you're his sisters Huh? He's not Just A Sister-con but he's also In Love with A Goodman Wha- OOF!!"

Penny then moving surprisingly fast for someone of her size then, Wacked up the head so hard he was sent flying into A Nearby Brickwall and smashed into it as Penny, yelled back!

Penny: "Yeah, The Cetacean Mammal that can Kick your Posterior! Let's go Big Brother Y/n."

She then Lifted up placing your head into her Bloated chest and began to waddle off as you tried to lift your head up to talk to her!

Y/n: "P-Penny, Why did you do that for me...?"

Penny: "Because I really care about you Big Brother Y/n, And I know how you feel about me. How he says... A Sister-Con."

Y/n: "W-WHAT!? H-How did you know!?"

Penny then Giggles and Hugs you even harder as you felt the softness and warmness of her body making you relax in her grasp, as she then explained!

Penny: "It's Like A Said A Billion times, You're as easy to Read as A Book, and I could tell you liked girls with A Far Higher BMI, So that's what I did, to Please you. Do you like it?"

You then Blushed bright pink as she smiled!

Y/n: "Y-Y-Y-Yeah, I really Like you A Lot, and You even seem super cute like that, and I think we could even- Chu!"

Penny then Kissed you on the Lips as you sunk into the kiss, as she hugged you harder making you sink into her Bigger and Softy body like one of those thousand dollar Mattresses!

Penny: "Like that?"

Y/n: "Y-Y-Yeah..." 'Wow, she can really read me like A Book!'

Penny: "So Why don't you take me to that Buffet you were Talking about Big Brother Y/n? Or should I say "Litte" Brother Y/n?"

Y/n: "No, please don't..."

Penny: "I just love teasing you Big brother Y/n! Love you!"

Y/n: "Yep, I know and I love you too."

One-Shot End!