Under-Expansion (All characters +18)

[Chara] Gooey Thighs part 1

(This includes thigh expansion, Chara and UnderTale belong to Toby Fox. All characters in this story are 18 and/or above)

Chara was sitting on the couch inside Sans' and Paps' house. She was stretched across the couch, she was watching the TV but wasn't paying attention.

"Ugh, I'm so bored... when the hell is Frisk gonna come back!?"

Sans passed by holding a bottle of ketchup "he'll be back when he's done training with pap and undyne" (for those who forget, Sans talks in all lower case.) Chara groaned "Whyyyy!? I'm so bored!" Chara slapped her lap in frustration. "if you're so bored then look around. there's probably plenty you could do, kid" Chara said "Why should I listen to ketchup suckin' bone bag?" Sans stopped in his tracks and turned his head towards Chara. No pupils.

"excuse me, you little brat?"

Chara said "Why should I listen to a short bone bag who's more ketchup then bone!"

Sans' blue glowing eye looked at Chara. Then traveled up and down her figure. Chara was dressed in her trademarked Green and Yellow striped sweater, a pair of brown shorts that fit snug over her wide hips and meaty thighs. Sans' smile widened. "that so, kid? well... let's fill you with something!"

"Huh!? What are you talking ab-O-OUT!?"

Sans slapped his boney hand on Chara's thigh. A loud slap following. "AH! WHAT THE FUCK!" A cold fluid, goo like started to course through her veins. Chara started to shiver feeling the goo build up. "Wh-What did you d-do!?" Sans let out a chuckle "ain't it obvious?" Chara's thighs began to expand slowly. Chara let out a soft moan, becoming mildly aroused by this. Sans said "seeya in a few hours thunder thighs! haha!" Sans walked out the door, leaving Chara to her growing thighs.

Chara looked at her thighs. They had grown alright. As if someone had taken a bucket of lard and poured it in each. Chara stood up. "A-Ah shit!" The new weight was a surprise to her. Chara had to keep her stance by leaning against a wall. Her palms flat against it, her thighs still growing. "W-Why does this f-feel so damn... GOOD~" Chara's moans quickly filled the house. Her thighs had expanded to double their original size. Her shorts started to stretch. "O-Oh my god!~" The sensation of the goo filling her thighs was driving her mad. The chill, the weight, the softness, it was nearly orgasmic. Chara tried to waddle to the kitchen, finding her expanding body making her a bit peckish. Each step made her lower half jiggle, when she reached the door way to the kitchen she stopped short when she felt it... the sides of the door frames... pressing against her massive thighs... "... Sans... you better FUCK me after this or another genocide is gonna happen soon."

Sans returned 3 hours later drinking a bottle of ketchup. He walked in and saw the fruits of his magic. A thicc thighed brat. Begging for release. From the door frame, and in another way~

Sans walked up behind her and whispered in her ear "miss me?" Chara whined in response "W-With every bullet!" Sans reached down and rubbed her thigh, squeezing a moan out of the murderous brat. Chara looked at Sans and yelled "EITHER FUCK ME! OR WALK AWAY!" Sans then grabbed her massive thighs. They had grown to the size of 2 full grown adult pigs. He pulled her out of the door frame and threw her on the couch. Her shorts ripping, revealing her womanhood, Sans walked towards her, his eye glowing a purple and pink. Lust. Chara looked at Sans. She knew what was about to happen. And she knew... she was gonna love it~

(part 2 will be a lemon. And will be after the first Frisk story. Thanks for reading!)