"I'm gonna FIGHT her. That other Undyne."

Papyrus' head snapped up from where he had been concentrating on stacking logs, working hard on the house while his superior leaned on the work that he had already done. "WHAT?"

She sneered in the drizzling rain and said, "You heard me."

Perhaps it would have been more productive for her to actually be helping with the construction of the city instead of brooding and staring off into the rain, but Lord knew he wasn't going to be the one to tell her that. Hell, she probably already rebuild her house in the amount of time it took most monsters to so much as move their stuff above ground. Papyrus just shouldered another huge log and fitted it into place, struggling to visualize the house that he and Sans lived in back in the underground. It was starting to take shape; it wouldn't be too much longer before he had to start thinking about the roof.

This would be a whole lot easier if his brother was actually here to help. But that ungrateful little sack of shit was probably off throwing tin cans into the mountain and lugging rocks at tiny birds, or...

Undyne rewarded Papyrus' silence with a swift kick to his shin, which luckily was still encased in armor. "Yo, maggot, you did hear me right?"

"WHAT? ERM..." he scratched his skull and put down his burden. "WHY DO YOU WANT TO FIGHT THE OTHER UNDYNE?"

Satisfied, Undyne huffed and stuck her hands in the pockets of her leather jacket. The rain made her slick fishy skin glisten whenever she moved her head. "Two reasons, both about one thing: She's me. One... Meeting another version of myself is on its own a great opportunity, isn't it? I've never been defeated before."

"WHAT ABOUT THE TIME WHEN YOU FOUGHT FRI-"

"I've never been defeated before." She squinted, and though Papyrus itched to go back to building the house, he didn't like the idea of that squint turning into something nasty. Frowning, she continued, "Somebody using cowardly tactics doesn't count. But I want to feel like someday I could be - I want to get into a battle with somebody as great as I am. Or, considering the kind of world that she comes from, at least half as great."

Papyrus screwed up his bony face. "AND THEN GET DEFEATED BY HER?"

"No!" A clang resounded through the rain as she kicked his armored shin again. "I want to win, I want to pulverize her. But... I want it to mean something when I do. And that just isn't something I can get here."

"OH." With a frown on his face Papyrus to look over at King Asgore, ruler of the monsters at LV 20, who has never been defeated in battle. With an emotionless expression he directing a group of underlings in rebuilding his castle, dark armor glinting in the dim light. "I SEE?"

Turned half-away from him, Undyne wasn't looking in his direction but instead had started to look out towards the human city in the distance. As the rain slowly let up, the lights were becoming clearer. As the day slowly turned to night, the lights were becoming brighter. "Two. It bothered me when we were there, seeing somebody go around with my face, being a nice sappy little shit to all the monsters, and especially to the humans. Made me sick, actually." Stretching her arms out wide, she cracked her knuckles. "If she's gonna continue sullying... me... like that, I'll just have to go make sure we don't have the same face anymore."

"UM-" Papyrus twitched, and Undyne glared his way. His armor was the only thing that gave him the strength to continue, "I GET THAT YOU LIKE FIGHTING? BUT I DON'T THINK THAT WE SHOULD BE ATTACKING THE OTHER MONSTERS IN THE BLUE WORLD FOR NO REASON? ...? I THINK THAT FRISK WOULD GET UPSET AND ASGORE MIGHT GET UPSET AND THAT OTHER SANS WOULD GET UPSET AND..."

"Jesus Christ," Undyne said, folding her arms. "Since when am I the only one of us that likes to fight? Number one that 'Blue Sans,' as they call him, doesn't scare me and he's not even gonna be involved. Number two Frisk and Asgore don't have to find out if you don't tell them."

"BUT IT COULD GET OUT."

She shrugged. "Alright well, I won't just attack her. I'll just challenge her to a duel. If she's anything like me, she'll accept, and nobody can complain that we end up fighting. There's nothing wrong with me doing that, is there?"

Papyrus leaned a hand against the frame of his unfinished house, as the rain became a quiet drizzle. He grimaced, as his not-stomach flipped in a knot. Undyne had one of those smiles on her face, a kind that he'd seen before in some unpleasant circumstances. "OKAY, WELL." He sputtered, groping for the words, and ended with, "WE CAN'T REALLY GET BACK THERE ANYWAY SINCE SANS HASN'T GOTTEN HIS MACHINE UP HERE YET."

This, at least, gave her pause, and she shrugged as Papyrus measured up the doorway with his thumbs and forefingers. "I guess you have a point about that."

"YEAH EXACTLY, WHO KNOWS HOW LONG IT WILL TAKE TO FIX UP HERE ANYWAY?" He jerked, suddenly; it was as if someone was planting him ideas, they came to him so fast. "ESPECIALLY SINCE EVERYONE IS. YOU KNOW. BUSY TRYING TO BUILD THE NEW CITY."

"Yeah, yeah." Undyne leaned back and look out over the moody expanse of clouds. Papyrus himself didn't like to see how much open space there was between himself and the ceiling of this world. "I guess I have to put this on hold no matter what I do."

And he honestly hoped that was the end of it, as he fitted a door in the frame and willed it to fix in place. But Undyne pushed off, folding her arms, and she said, "Keep on eye on things, though. As soon as Neo New Home is finished - as soon as Sans' machine is ready - I'm going to that other world and I'm kicking the shit out of that other Undyne."

Papyrus didn't say anything, and having made her declaration Undyne just walked past with that wide pointed smile. He brushed the lingering traces of Snowdin snow off the roof and contemplated getting it all the way on top of the house.

Maybe he should find Sans for this.

Author's Note: Note for people not on AO3: This story takes place in the Bunny Fell-Fell series, of which "The Many Worlds Theory Sucks" and "This Game is Too Hard" are earlier installments. I don't think it's necessary, though, to read the other two stories to understand this one. The main thing to understand is that it features Underfell and Undertale universes that are aware of each other and both of them are post-pacifist.

SO. Here we go on the next fanfiction for this series. It's a brand new story so I've got more interest in it and hopefully that translates into more frequent updates! I'm using a dictation software to write some of this though, so expect some weird typos.

Now... I haven't written a lot of Fell Dyne or normal Undyne, but I'm hoping I'll get a much better handle on her with this fic ;w;

Next Chapter: Unfamiliar Waters