Location: The Underground Realm

No POV

Somewhere in the Underground Realm, we see an interdimensional portal in the snowy terrain as we see a skeleton wearing a blue hoodie, a white shirt, black shorts and pink slippers come out of the portal and landed on the snow. Then when he got up from the portal, he looked up to see that the whole place looked exactly the same place he's been in, which was really confused to why he ended up in the same place where he met the child named Frisk.

Sans: What the? That's odd. The portal somehow just teleported me to the entrance to the Ruins where I met that human kid. Oh well, I might as well head over to Grillby's then.

So, Sans walked down the path to head to Grillby's unaware that someone is watching Sans from the trees as the mysterious figure followed Sans as the skeleton was just walking down the path until he heard a loud crunch sound as he turned to see that large stick was stepped on.

Sans: That's strange. I think someone is following. (Looks around before shrugging) Oh well. Must be my imagination.

Then as he walked up to the bridge, he stopped for a moment to take a look at the poorly made wooden bridge, before heard sudden footstep coming towards him until it stopped behind him as someone with a blue and orange glowing pupils as he spoke to Sans in a deep, demonic voice.

???: Hey...Bonehead...Don't you know how to greet a new pal? Turn around and shake my hand.

For some strange reason, Sans had never felt the feeling of fear like this before as he slowly turned around to face the monster behind him that pulled out his hand and he can see the intense orange and blue glow on its eyes and wicked smile as Sans carefully pulled out his hand and his grabbed the monster's hand to shake it.

Until.....

PPPPPPPPFFFFFFFFFFFFFFFFFFFFFFFFFFFFHHHHHHHHHHHTTTTTTTTTTTTTTTTTT!!!

Sansfield: (Chuckles) Oh man...the old whoopie cushion in the hand trick. It's ALWAYS funny.

Sans: (Surprised then laughs) Alright you got me. That was a good one.

Sansfield: Thanks. Sorry for scaring you like that.

Sans: Nah, it's all good. I'm used to it. Who are you by the way? You look kinda like me, but a cat.

Sansfield: Who am I? I'm Vs. Gorefield, but you can call me, Sansfield. Who are you?

Sans: Who am I? I'm Skeleton Bros, but you can call me, Sans. Sans the Skeleton.

Sansfield: Nice to meet ya, Sans. What brings you here in my universe.

Sans: I'm not sure. One minute I was talking to this human named Frisk and the next thing you know I fell into a portal and ended up here.

Sansfield: I see. Wanna head over to Grillby's? We can chat over there and I'll explain about this universe. I'm buying.

Sans: Sure. I got nothing better to do, so why not.

Sansfield: Cool. I know a shortcut to get there faster.

Sans: Alright then. Lead the way.

So, then the two of them head over to Grillby's through a shortcut as Sansfield started explaining about his universe that has a completely different backstory than where Sans came from since the monsters lost the battle against the humans and were forced to live underground, where Sansfield came from is that everything up in the surface was peaceful until it all ended when the Mondays came in to create a world filled with nothing, but chaos and destruction.

Sans was both amazed and shocked when Sansfield explained the whole 'Monday' thing in his universe, even after he and the others lived in the underground world where Mondays never existed.

Sans: Wow. That's an interesting story.

Sansfield: That's what happens when you had a bad Monday in my universe.

Sans: That makes sense. At least the Mondays aren't as bad in my world, but who know what happens in your universe at any given moment.

Timeskip - A Few Hours Later

After the two monsters had their fun at Grillby's, they decided to take a walk in Snowdin before Sansfield spotted something in the snow under a pine tree as he walked closer to the tree to find...

A piece of paper?

Sansfield grabbed it and suddenly remembered something about finding a note under a pine tree in a snowy biome as he placed the note inside his jacket to check it out later and meet up with someone to read the note later.

But then....

???: I told we had to make a left turn to get here.

??? 2: Beep Bop Boop Bop Beep! (Well, excuse me for not getting the right directions to get to Snowdin)

???: You know I can't understand your language! Can you even speak English at all?

??? 2: Skedo Boop Bop Beep!!! (Hey! It's not easy to speak normal you know!)

???: UGH! You're starting to annoy me, blue hair dwarf!

Then Sansfield turned to see both BF and a grey tabby cat by the name of Nermal, who currently look like crap after having to deal with a problem that happened in an alley during a terrible thunderstorm before he met BF and ended up in the Underground Realm with the blue haired dwarf. Sansfield somehow remembers seeing that "Blue haired dwarf" before and he never thought he would see Nermal all stressed out before or the fact that he's a bit older than he originally was. This made the skeleton cat feel interested to know more about Nermal as we see Sans appearing in front of the two since Sans knew BF a lot in various fnf mods including the Skeleton Bros. FNF Mod.

Sans: Hey, Boyfriend. Nice to see you again.

BF: Beep. (Sup Sans)

Nermal: Who are you?

Sans: Who am I? I'm Skeleton Bros.

Nermal: What?

Sans: Didn't get the joke? Well, let me try this again. I'm Sans, Sans the Skeleton. What's your name?

Nermal: Oh, it's Nermal.

Sans: Nermal, huh? Nice to meet you? You look like you needed some sleep. I bet your eyes are screaming, "I need sleep!", am I right?

Nermal: Not really? I don't want to talk about it right now.

Sans: Oh, alright then.

Then Nermal looked at Sansfield with a look of surprise as he looks exactly like Garfield but as Sans the Skeleton as the skeletal cat introduces himself to Nermal.

Sansfield: Nermal. I'm Vs. Gorefield.

Nermal: Garfield? Is that you? Why do you look like that? Is this some sort of prank or something?

Sansfield: Not really? I always look like this, and my name is Sansfield. I may look like Garfield, but we're not the same cat.

Nermal: Ok?

Then Sansfield looked at BF that was a bit confused to see someone that looks like Garfield and Sans combined as he pulled out his paw to let the young rapper to shake his hand to properly introduce himself.

Sansfield: You must be the young rapper named Boyfriend. It's a pleasure to meet you.

BF looked at his paw for a moment before he grabbed it to shake his hand, only for him to experience intense flashbacks as images of his past experience in another universe with a man by the name of Jon Arbuckle, the monster known as Gorefield, Jon's old roommate, Lyman that developed Super Saiyan Powers and the angel that saved him from certain death before returning to reality with Sansfield, Sans and Nermal have worried and concerned looks on their faces.

Sans: Hey kid. You alright there?

Nermal: Wonder what got him so riled up like that?

Sansfield: I don't know. All I did is asked him for a handshake and then he went all crazy like he's nuttier than a squirrel's lunchbox. (Rimshot)

Then Sansfield noticed the heart shaped locket around BF's neck and inside the locket has a golden cross in it along with a picture of his beloved fiancé, Girlfriend as the holy power of the golden cross did not harm the demon girl at all as she managed to use her demonic powers to transform the golden cross into the heart shaped locket to not only add the picture of them together in the locket, but also hide it away from her overprotective father Daddy Dearest from ever finding out that BF got the cross from the Son of Godfield himself.

BF then managed to regain his composure and after he felt that shock from shaking Sansfield's paw, he figured that he is actually the same angel that saved his life and gave him the golden cross as a gift as he brought out his microphone to challenge Sansfield.

Nermal: Huh? (Notices BF pulling out his mic) What are you up to now, kid?

Sans: Oh. He's actually challenging Sansfield to a rap battle. I know that cause we had a few rap battles here and there and he's always up for a challenge.

Nermal: Is that so? Well, I guess this should be interesting. I mean, what could happen at a place like this?

Sansfield: So, you want a rap battle, huh? (Summons a mic) Then I accept your challenge. You ready?

Boyfriend: Beep Boop! (Bring it on!)

Song Plays - Cat Petalla - BF Vs. Sansfield - Vs. Gorefield V2 - FNF Mod

https://youtu.be/e9RXftYWDyE

As both BF and Sansfield started the rap battle, the first part of the song went well until the scene changed to the Undertale battle screen with Sansfield on top of the text box with several bones hover around him in a circle with BF, Nermal and Sans inside the box with BF's locket having a glowing golden cross inside as the three of them see Job walking into the box with an annoyed look on his face as he asks where his pipe is.

Jon: Where. Is. My. PIPE?

Then Sans suddenly found the pipe that was stuck to BF's back as the young rapper replied to Jon with a Beep as it is his turn to rap against BF until he eventually got blown up by a bone that appeared inside the box as BF and Sansfield continued the rap battle until the end of the song and this chapter on a cliffhanger.

-Song Continues Until the End-

TO BE CONTINUED IN PART 2