Waterfall doesn't seem deserted like Snowdin. I can still hear playful footsteps, and some faint distant voices. Granted, it could just be some echo flowers, but either way, I feel comforted with the background noise of other monsters.

I reach my best friend's house and when she opens the door, she can instantly tell something is wrong. Either she knows me really well, or my face gives me away.

"Hey Pap! Oh... you look like hell. Get in here." Undyne pulls me toward her by my arm and shuts the door behind me.

"What's up? What's going on?" She sits us both down on her couch.

"UH" I look around the room uncomfortably. "... IT'S SANS." I force myself to breathe. I'm not really ready to talk about this yet. She just looks at me, patiently waiting. "HE... HE'S DEAD." My voice cracks, and my hands cover my face.

I hear her quite audible gasp. "Paps! You... you can't be serious." My sobs and tears convince her that this is not a prank. She pulls my hands away, and her hand cups my face, beckoning it to look at her. "Pap. Who did this?! I will rip their guts out through their throat!" Then, her arms wrap around me aggressively; she's hugging me. I don't feel very comforted at what she just said, though... she can be a bit violent.

Though, isn't that the reason I came here?

"I'm so sorry, Pap. You know you can stay here with me, right? You don't need to be alone right now." I nod into her shoulder. "You know I'm here for you." I nod again. "You know I'll kill whoever did this. And not quickly either; I want them to suffer! I'm not going to let them off easily. First, I'll-"

"-UNDYNE." I interrupt her.

She sighs and returns her attention to hugging me.

"...I NEED YOUR HELP."

"Of course. Anything, Pap."

"I... KINDA DISCOVERED THAT BREAKING THINGS HELPS ME FEEL BETTER... AND I-"

"-Say no more!" She interrupts me and jumps up off of the couch. I look up at her, and she starts pulling me to my feet. She takes my hand and leads me to her kitchen. She makes a spear appear out of thin air, and hands it to me. "Okay. Smash the table."

In a normal situation, I would have hesitated, resisted, and argued. But this is no normal situation. My pent up frustration, even just from the time it took to walk here, has me ready for another outlet. Plus, arguing with Undyne always gets me NOWHERE. It's like arguing with a wall. A loud, opinionated wall. Or Sans...

I take the spear.

With a loud grunt, I throw it into the center of the table with all my might.

...Are you kidding me? It barely left a scratch! Well, I didn't use all my might... I started off easy... heh.

"Come on, Papyrus! Is that all you got?! Don't be a chicken, smash my table to pieces! Like this... NGAHH!"

She jumps into the air, spear in hand, and lands on the table. Well, lands isn't the right word. She crashes into the table, completely breaking it in half!

"Your turn."

There is no way I can follow that up. That was awesome! I take my spear, and just start hitting one half of the table with it, over and over. It begins to crumble to smaller pieces, and the rush takes over me again.

Undyne does the same with her spear to the other half of the table. Doing this with my best friend heightens the feeling, and in this moment, I am almost happy. The kitchen is filled with echoes of our loud grunts and yells of anger, until the table is unrecognizable pieces of wood scattered all over the floor at our feet.

Undyne and I look at each other, panting. She is halfway smiling at me, until her face drops into a frown. She turns around and punches the wall behind her. "Ngahh! Sans! Why did this have to happen to you!?" She leans forward, resting her head on her arm on the wall. Her shoulders begin shaking as she starts crying. I run to her immediately.

I start crying again too, as I pull her into a hug. We stand there, hugging and crying into each other, for what must have been an hour.

Misery loves company, right?

I break the silence. "I WANT TO HELP YOU."

She pulls me back to arm's length away from her. She gives me a serious look. I keep my resolve. "I WANT TO HELP YOU KILL THE HUMAN."

Her blank, hard stare glares back at me.

One nod.

"Let's go get that punk."

...

I never actually plan for Undyne in my stories, but she always shows up.

Sorry guys, no house fire.