Hi, everybody! This is a prequel to the fourth chapter of "Lights and Shadows", Omega Ultra's collab fic, showing more or less what happened before the main heroes arrived.

Anyway, if this contradicts the story in any way, you can consider this non-canon.

That being said, read and review, and I hope you enjoy. :)

(Gravity Falls, main street)

A purple portal opens above the town of Gravity Falls, and from there hundreds of shaddolls jump out, causing huge ruckus and panic amongst the citizens who spot them. Among these shaddolls, a white orb pops out of the portal, with the nearby shaddolls trying to reach it with no avail.

And then, just as some more shaddolls appeared, a triangle formed in the middle of the street and, as it glowed an intense white light, it transformed into the inter dimensional being known as Bill Cipher. "Alright, let's see what's all the ruckus abo-" and then the orb falls on top of Bill and into his hands. "Ouch! What in the blazing-hey."

Bill inspected the orb and laughed a bit with excitement, right before a shaddoll hound suddenly snatched it away from him. Noticing this, Bill eyed the hound with anger as he charged a fireball and shot it, only for the shaddoll to jump into a portal that opened and closed once it went in, though the fireball managed to hit some nearby shaddolls regardless.

Angered, the floating triangle snapped his fingers and looked down before hearing somebody screaming. He turned around, and saw the people of Gravity Falls running around in fear, with some being grabbed and turned into purple-skinned, zombie-like beings by the shaddolls.

"Oh, wow, look at this place! Gravity Falls has definitely seems more interesting for once!" Bill exclaimed before spotting the shaddolls. "Though I do have to question, where did these things come from?"

One of the shaddolls lunged for Bill, only for him to be "eaten" by the dream demon, who waited for a moment before "spitting" the creature out. "And why do they look like they come from a children's card game?" the dream demon scratched his non-existent chin and quickly got an idea. "It's just a guess, but I have an idea of who could be responsible for summoning these things."

And with that said, he vanished into thin air, somehow unleashing a burst of energy that paralyzed the creatures caught in the radius.

(Gravity Falls Maximum Security Prison, Gideon's cell)

The shaddolls attacked and confronted both Gideon and his "henchmen", who could barely fight back the demonic creatures. Most tried to punch them, but it didn't do anything, and when the shaddolls counterattacked, they almost greatly damaged them without much effort.

However, once Gideon's last man fell, Bill materialized in the room and paralyzed the shaddolls, before snapping his fingers and lighting them on fire. Then, as the shaddolls screamed in agony as they turned into ashes, Bill slowly turned to the albino, though he only greeted him once the shaddolls died. "Hi, ventriloquist dummy!"

Gideon stood his ground and gave the demon a furious glare. "Hey, I gotta ask you something, did you summon these things?"

"No! They-they just appeared out of nowhere!" Gideon replied, partially afraid, partially angry.

"Not exactly, they came out of a portal that opened without my permission to do so." the gloating dorito clarified, shaking his fist as he continued. "Some portals can be quite rude sometimes."

"What are you doing here, anyway?"

"Well, I wanted to ask you if you summoned those things." Gideon rolled his eyes as Bill glanced at the defeated men. "But now that I see you have valuable "henchmen" in this place, maybe we could make a deal."

The chubby kid, having dealt with the demon before, wasn't particulaly thrilled at the proposition. However, once he checked the situation and saw it was the only way he would come out alive, he crossed his arms as he said, "Okay, what are the terms?"

"You see, I had a shiny white orb in my hands when this started, but it was snatched away by an insolent hound before I could do anything with it!" the dream demon replied, earning a scowl from the kid in response. "However, that's not relevant to the deal. The terms for it are that, in exchange of giving you and your men equipment that could help you defeat these things, you will help me find another color orb to use for my plan, and make sure neither Pine Tree nor Shooting Star get to it first."

"What about Stan?"

"Oh, don't worry about that old guy, once I get the orb, I'll take care of him."

Bill set his arm on fire and extended it forward to Gideon. "So, deal?"

The boy hesitated for a moment, swallowed his hesitation and sealed the deal...or he would have, had Bill not backed away at the last second.

"Oh, right, I just remembered! Last time we made a deal, you double crossed me!" Bill stated before extinguishing the flames and flying away. "Maybe I should leave and let you be eaten alive by these shadow freaks instead."

"No! Don't do that! My own men can't handle these things, we're gonna die if they attack again! You need to help us!" Gideon pleaded, much to Bill's indifference. "I-I'll do anything to get your help! No tricks this time!"

This got the demon's attention, who immediately teleported back to the chubby albino. "Anything?" Bill asked with a glowing, red eye and a deep, demonic voice.

Gideon flinched and, once the shock wore off, nodded in response. Bill laughed a bit as he lit up his arms once more. "I'm all ears."

(Meanwhile, at the mystery shack's underground laboratory)

Dipper, Mabel, Soos, Stan and Stanley stood in the middle of the ruined laboratory, Dipper looking shocked and amazed at the same time. "Wow, that was quite the adventure."

"My favorite part was the one I didn't hear!" Soos suddenly said.

"Soos, you didn't hear the story." Mabel remarked.

"And that's why I loved it!"

Then, just as the twins and Stan laughed, Stanley felt something and turned to the portal, which blinked from it's light blue color to a purple one repeatedly. He narrowed his eyes and walked closer to the machine, only for the ground to shake like mad as some purple electricity came out of the portal. "Stanford, did you miscalculate something while building the portal?"

"No, I'm pretty sure I followed all the instructions up to the tiniest, most insignificant detail!" Stan replied as he tried to hold his ground.

The portal became purple, and some shaddolls started to come out through it. "I think we should leave!" Dipper expressed.

The rest agreed unanimously and tried to flee as fast as they could, though Soos was caught by one of the shaddolls and dragged directly into the portal. By the time the team had noticed this, the door behind them closed and they turned to the window, watching helplessly as their friend was overpowered by the things. "Soos!"

"Go on without me!" the man exclaimed as he was dragged into the portal.

Once he went through, much more shaddolls came out of the portal, and they tried to bust the door open as the team went to the elevator, which closed it's doors as the door was destroyed and the elevator was pushed upwards by the monsters.

It was pushed so far up, it actually went through the roof of the mystery shack, and fell at a nearby table Gompers was eating, destroying it upon contact. Once that happened and the elevator opened it's doors, the team came out and relaxed for a moment before they turned to see a horrible sight:

Hundreds of shaddolls erupting from the crack in the mystery shack, including some affected tourists, who wandered around the place aimlessly. "What happened to those tourists?" Stan questioned.

"More importantly, what are those things?" Dipper asked, focusing solemnly on the shaddolls.

"I can answer that question!"

Hearing that, the team looked around until Bill formed in front of them, shocking them in the process. "These are inter dimensional beings that have come here to destroy gravity falls for whatever reason." "And you know, I might be able to lend you a hand, if you're willing to make a deal that is."

"I should know I would see you sooner or later." Stanley uttered.

"First you attack Stan's mind, then you possess my body, and now you unleashed these things just to force us into a deal?" Dipper recapped.

"That's low, Bill, even for you!" Mabel hissed as she pointed at the isosceles monster.

Bill simply laughed and shook his...self, before answering, "Pine Tree, I know you're a paranoid, pathetic excuse for a detective-"

"HEY!"

"And Shooting Star, I know you only act this way because you think I'm the hottest creature in all of Gravity Falls-"

"Only in your sick dreams!"

"But if you will go with the theory that I summoned these things into Gravity Falls, I'll let you know about it's holes." Bill paralyzed a nearby shaddoll and tried to make it into his minion, without any success. "First of all, If I unleashed these things, why can't I control them?"

"Hmm, they don't look like they're affiliated with anybody." Dipper remarked.

Then, as the dream demon said the next thing, he threw away the shaddoll, which screamed before hitting the ground and exploding...for some reason. "Second of all, how could I have done a deal with them? I can only do that with sentient beings, and as far as I've seen, these things have the sentience of a peanut."

The team then heard something searching something, and they turned to see a shaddoll fighting one of the Sev'Ral Timez brothers for a piece of meat. "And third, and the biggest flaw, why would I unleash something I myself cannot control?"

"You have done that before, just ask Gideon." Dipper smugly replied.

Mabel and Stan went "Ooooh!" while Stanley raised a confused eyebrow.

"In any other situation, I would be mad at your comment, Pine Tree, but this is a situation where you need my help." Bill confidently retorted. "Or you make a deal with me to get someone to help you destroy these freaks, or you watch as Gravity Falls...falls, to these things."

The team thought about it and, after seeing the current state of the city, they decided to do so on one condition: "No tricks or exact wording!"

Bill nodded, formed four arms and set them on fire, which he extended to shake with the team's hands, sealing the deal. After that, he turned back to normal and watched as the team turned to see the city's main street briefly illuminated by a white light. "What happened?" Dipper questioned.

"My end of the deal, of course." Bill arrogantly answered. "The terms of the deal are that, in exchange for helping me get something I need, two heroes from another dimension would appear in the city, ready to help you defeat these shadow-"

However, Bill shut his trap once he noticed that the team had suddenly vanished. "Where did they go?"

And then, with little to no warning, the stanmobile came out of the mystery shack and sped past the dream demon, who managed to spot Stan driving it like crazy, and the twins gripping the author, all three with horrified looks. "Stanmobile, suckers!"

"Hey! Wait for me!" Bill complained as he followed the vehicle.