It was a normal...you know what, let's just skip the intro. All you need to know is Papyrus is at Undyne's house.
"Woah, Papyrus! Check it out! Mettaton is holding a cooking contest tomorrow! We HAVE to win!" Undyne said, looking at the UnderWeb.
"AHH, THE GREAT PAPYRUS WILL FINALLY GET TO USE HIS PERFECT SKILLS, ALONG WITH THE ONE WHO TAUGHT ME!" Papyrus said, gleefully.
"Glad to have you on board! Now let's get cooking!" Undyne said, accepting the challenge.
(Later...)
"Alright! Attempt number 1 is done! Now to test it!" Undyne said, taking the clearly overcooked spaghetti out of her oven.
"Mm...a little hot...maybe there's some part that's still good!" Undyne said, as she gobbled up the entire plate of spaghetti.
"Nope..." She said.
"IT'S ALRIGHT, I, THE GREAT PAPYRUS, WILL TRY IT MY WAY!" Papyrus said.
(More time later...)
"Mmf...that's way too cold, Papyrus!" Undyne said as she took a bite.
Many, many failed attempts that Undyne had to eat, and only now was she felling the effects of all that pasta.
"Al...alright, Papyrus, I think we should pick this up again, later." Undyne said, trying not to look green.
"WHATEVER YOU SAY, UNDYNE!" Papyrus said, before jumping out the window.
Undyne sat at her table, clutching her aching and bloated belly. It looked as if she had swallowed a bowling ball, and it felt like it to Undyne. It churned and gurgled sourly as her fingers kneaded to blob of flesh like dough, hoping to soothe the pain. She eventually fell asleep on her table.
When Undyne woke up, she found a note, clearly from Papyrus saying. "I came back and you were sleeping too soundly for me to wake you. I made another batch, but I think I made too much." Undyne looked at the giant pot in front of her, filled with spaghetti. The thought of eating more nauseated her, but she knew she had to at least try it. It actually tasted really good! Even though her stomach said no, her tongue said yes. She ate so much more than what she planned. Sphere belly now could hold a couple of bowling balls, but during her nap, Undyne was definitely...chubbier. Her butt had bubbled up quite a bit, her arms and legs looking meaty, but her breasts didn't grow that much. Even her face was rounder.
Eventually, Papyrus came back to get the spaghetti and Undyne.
"(Oof! *Groans*) Sorry, Papyrus, I'm feeling a little sick..." Undyne said, as she continued to caress her blob of fat. "Maybe you could go and represent me, too!" She offered.
"OH...OKAY, I'LL DO IT!" Papyrus said, taking the door on his way out.
Undyne tossed and turned on a nearby couch, when eventually, she felt the urge to go.
After using the restroom, Undyne felt so much better, a little hungry, even. Her stretched stomach wanted to eat, surprisingly.
Undyne went to her fridge and opened it up to find more pots, similar to the one she found on the table. 'So this is what Papyrus meant when he made too much. Oh, boy...' She thought.
She sat down with the first pot in front of her. She began to eat it. A but cold, but still great! In fact, she didn't want to stop! She just kept shoveling the pasta down her throat.
Undyne now sat in the floor, since she ran out of room on her table, and that she broke her chair. She had eaten EVERYTHING! All the pots, in her gut.
Her belly looked as if she held a beach ball captive in there. Her arms were as fat as her thighs originally were. Speaking of her thighs, they know looked like chicken drumsticks that would feed a T-Rex. Her face had rounded out so much, it really showed the green she was feeling. Her stomach visibly churned and gurgled as it struggled to digest the monster within.
"I don't think this can get any worse" Undyne thought to herself. Then, Alphys burst though Undyne's door, holding a new anime that some unfortunate human dropped on Mt. Ebott.
"UNDYNE! I FOUND A NEW ANIME! WE GOTTA...oh..." She said, before her face turned red. "W-what happened to you?"
"Long story." Undyne said. "There was a LOT of spaghetti involved, though."
"I can see that." Alphys said, looking through Undyne's cabinets finding MORE spaghetti.
"Oh, no," Undyne whimpered.
"D-don't worry! I can eat this for you!" Alphys said, trying to keep Undyne happy.
"Really?!" Undyne was so shocked, she bounced up and belched. "Excuse me...I might be a little gassy from all the Parmesian Cheese..."
"I-it's no problem!" Alphys said, as she began to indulge on the noodles. "Ooh, wow, this is GOOD!" She said. She continued to stuff herself.
Now, Alphys did always have a rather large apetite, and it showed on her normal figure, but the spaghetti proved it could round her out easily, too. It quickly shloshed its way into her stomach, and eventually, like Undyne, the more more she ate, the more it felt like she was trying to digest a boulder. After a while, Undyne had fallen asleep from her stuffing. The only way, Alphys knew this was because she heard Undyne fart in her sleep, which Alphys knew that Undyne would never make a display of her flatulence with company.
After a while more of stuffing, Alphys needed a break. She remained on the floor as she tried to soothe her tummy which felt like it could explode. She gave up on rubbing it and just sat there...until her belly started to make stranger noises. Her stomach began to puff up from her own gassiness. She belched and rarely farted a few times to make her belly feel better.
Speaking of her gut, it had gained 4 new fat rolls. Her thighs had grown immensely, while her breasts grew enough to sit on her belly. Her chubby cheeks forced her glasses upward. Yet she still had 3 pots left.
She struggled to stuff the bites in her mouth as her tummy would not settle down! I shifted and gurgled and bloated from all of the grated cheese. Unlike Undyne, Alphys' lab coat could stretch all that great.
As Alphys finished the final bite, the buttons could take no more as they flew off and hit Undyne in the face, waking her up.
"OHMYGOD! Undyne! I'm so sorry, I-" Alphys began, belly bouncing, revealing an anime bra.
"(Burp Ooh,) It's okay, Alphys. How could I blame your clothes after the huge favor for me? However...it does look like the effects of out overindulgences has stuck us her for some time." Undyne said as she struggled to get up.
"Hey, Undyne," Alphys said, sinisterally.
"What?" Undyne asked.
Alphys grabbed a huge pocket of fat on her. "I think I'm fatter than you."
"I'd accept that challenge, if I could move!"
The two laughed and talked and passed some form of gas for the rest of the evening.
