Underfalls: The COMPLETE Trilogy To A Gravity Falls/ Undertale Crossover

❤️Chapter 6: Just... Trust Me...❤️

SansPOV

"Wait... You have?" I was seriously shocked. So it was true. Mabel is talking to the same flower that Papyrus has. "W-what did he say to you?"

Mabel looked down at her fries before speaking. "There was a lot he said to me and Dipper... But there was one phrase that really stuck to me in particular..."

"What was it?"

Swallow.

"In this world... It's KILL or BE KILLED..."

My eyes widened. Kill or Be Killed? I knew that flower was no good but... Kill or abe Kiled? Did he tell Papyrus this as well? I took a shaky breath before speaking again. "A-and did either of you take his advice?"

"Actually... I think Dipper has... That's why he went killing everyone... Even Papyrus..."

"Ugh, don't remind me..." I sighed, leaning against the counter. "But uh... Can you... Can you keep a secret?"

"Y-yeah..." Mabel blinked a couple times before turning to me. "I.... For a few weeks now, Papyrus has been telling me about this friendly little flower that he talks to everyday. At first, I thought it was just some joke that my bro was falling for, until you said you saw him too."

"It wasn't that long after we fell, either. Like, he was about to kill us when-"

"He was going to kill you?!?"

"But Toriel saved us! Without her, we would've died right there on the spot."

As I listened to Mabel, it seemed like she was in more stress than I imagined. Pehaps I should tell her what I know. With both of our minds together, we could resolve the suspicions that I feel. There was something else going on... I could feel it.

"Uh.. Mabel?"

"Yeah?"

"Do either of you know anything about a timeline?" She shook her head, just as I thought. "W-well... That's actually pretty accurate. Most don't know what the timelines are."

Pause.

"The timelines are a series of endings that occur depending on a human soul's actions. Depending on how many souls you take/spare, determines your fate."

"What does that have to do with me and Dipper?"

"A lot of things, actually. You see, you weren't destined to be the last human soul. Dipper was. He would've been the one to destroy all humanity if I didn't stop him. It was more than my brother I was fighting for. It was everyone. It was for you. And I know you'd hate me for killing him, but it's what I would've had to do. But, don't worry. The timelines should be over."

"Then why mention them?"

"Because," I murmured, twiddling my thumbs. "Chara and your little flower are still out there. And they're here to enslave this earth as their own."

Mabel just stared at me wide-eyed. Perhaps I had said too much. I frowned, as I hopped to my feet. "I'm sorry... I gotta go..."

•••

A while later, me, Paps, and Mabel decided to take a walk around on the surface, to try to relieve the stress that had been bothering us for some time. That's when we ran into him.

My eye started to flare at the sight of the boy. I still didn't trust him. But I quickly blinked the anger away as I remembered that I wanted to improve, and by that, I had to open up. Dipper blinked a greeting as he turned towards Mabel, giving his sister a hug. They started to have a little conversation to themselves, as I just stood there in thought. I was soon pushed out of it when Mabel yelled my name.

"Sans!"

"Y-yeah?"

"Dipper wants to know if he can tag along with us tonight? And maybe you can learn a lot about eachother!" Dipper shook his head, only requesting if they could hang out later on. I nodded, and soon the boy dissapeared in the shadows. It seemed off, but I ignored it.

But what should've known is that I ignored the wrong things.

NoPOV

Dipper walked through the empty clearing of Gravity Falls, a dark presence saunting in the air. "I did it, alright?" he muttered as he lowered the bill on his cap, hiding his frown.

What had he gotten himself into?

Author's Note: I apologize for the short chapters and the delays on updating. We need to get a new internet plan so I couldnt update until school. Anyways, I hope you've enjoyed this chapter