Dipper and Mabel were sitting at the table, having a syrup race when Soos ran into the room.

"Dudes! Dudes! You gotta see the news!" Soos told them, pointing to the living room. Soos ran into the room, Dipper and Mabel following suit.

"This is Chandra Hernandez at the scene of what looks like an alien UFO crash. Here we have a witness of the scene." Chandra said from the TV, turning the mic towards Old Man McGuckett. "What were you doing when you saw the UFO?"

"Well I was doing some work on my new invention, a high intelligence robot thingymajigy! When I saw this blue thing crash into the ground! It was hootin and hollarin like my raccoon wife when she hears a car horn!" McGuckett replied.

"As you can see here, the police force is currently trying to make contact with the UFO." Chandra said, and the camera turned to Deputy Derley and Officer Blubs approaching what looked like a giant bar of blue soap.

The officer and deputy were shaking in their boots as they knocked on the side of the ship.

Suddenly the door opened with a start, and a floating little light blue slug like creature with kelp like arms floated out of the ship.

"That thing is hideous! This is Chandra Hernandez, throwing up!" Chandra made a gagging sound and stepped out of the camera's frame.

THEME SONG

https://youtu.be/Z6usKhzL8uI

COMMERCIAL

"Great uncle Ford! Great uncle Ford!" Dipper shouted excitedly, standing up with a start. Stan and Ford raced into the room at his call.

"What is it Dipper?" Ford asked.

"Aliens!" Was all Dipper could manage, and probably all he would've been able to say since Ford immediately turned to the TV, which was now focused in on the alien.

"Incredible! Finally there's an extraterrestrial that could answer some of Gravity Fall's greatest mysteries! I must get down there at once!" Ford concluded and he hurried out of the living room, Dipper was about to follow when Stan stopped him.

"Hold on kid, there is no way I'm letting you get involved in all this weirdness again. Not after Bill, the giant ogre, and the evil skeleton!" Stan told him, and Soos tilted his head.

"Evil skeleton? Nobody told me about that one." Soos commented.

"Oh so this giant evil guy captured me and erased everyone's memories of me and then Dipper came in and we were all KAPOW! KABLAMO! And he was all like PHWUSH!" Mabel explained.

"See kid, look how easily your sister explained a traumatic experience. This weirdness is really having an effect on you two. Can't you just be normal kids and enjoy a normal summer?" Stan asked.

"Mabel is never bothered by any insane things." Dipper pointed out.

"I haven't had nightmares of Weirdmageden in months!" Mabel added.

"Plus do you really think that we can live normal lives in a town where ogres and giant skeletons are daily occurrences?" Dipper asked.

"Don't forget video games coming to life and evil triangles trying to take over the world." Soos commented.

"And also ghosts and mermen and vampires!" Mabel continued.

"Vampires?" Stan questioned.

"You people don't know everything about me." Mabel reminded them.

"I'm serious about a normal summer. At least stop looking for dangerous monsters. If they come to you then that's not your problem, but when you're following my brother on an expedition to meet aliens, that's on you. So you're staying here." Stan told Dipper firmly, and he glared at Stan.

"Well I'm off to meet some aliens everyone!" Ford announced while he was heading towards the door.

"Bring me back an alien sweater!" Mabel called and Ford laughed, then walked out of the Mystery Shack.

"Alright fine, I'll just be... cleaning up the gift shop." Dipper announced quickly, and he ran into the gift shop. Quickly he went to the vending machine, punched in the code, and took the elevator down into the basement.

The doors opened with a ding and he ran into Ford's lab, searching for something, anything that cool help him achieve his goal.

"If I can't come to the alien, then the alien just has to come to me." He muttered

COMMERCIAL

Later that day Ford still hadn't returned, and Dipper was still searching for something that could attract the alien in the basement. 

"Hey Mabel, do you know where Dipper is?" Wendy asked while standing at the register.

"I'm not sure, he said he was going to clean up the gift shop a few hours ago but I haven't seen him since. Maybe he's upstairs doing nerd stuff." Mabel suggested hopefully.

"Well if you need me I'll be up on the roof. If Stan asks where I went tell him I'm chasing off a bear that was attacking the face that looks like a rock." Wendy told her and Mabel gave a  thumbs up. Then Wendy climbed the latter up to the roof leaving Mabel alone in the gift shop.

"Hey dudes, get in here!" Soos shouted from the living room and Mabel ran in. The TV was on and it was showing the alien from before interacting with Ford.

"This is Chandra Hermanez with an important update on the alien situation. It appears a man similar to Stan Pines is making contact with the alien." Chandra whispered.

"Dipper get in here! Ford's on TV!" Mabel called, but she didn't hear her brother coming.

Meanwhile in the basement, Dipper was still poking around. He found a room with a bunch of giant glass tubes in it. There was a curtain covering one in particular, he made his way over to it cautiously.

"This seems familiar..." Dipper mumbled reaching for the curtain, he pulled it back to reveal the shapeshifter in his true form. "AHHHH!" Dipper jumped back in shock.

"How did he get here? Last time I saw him we froze him in the bunker. Wait, great uncle Ford must have brought him here somehow!" Dipper realized. "I wonder why..." Dipper leaned in close to the glass and tapped it, nothing happened. Suddenly a crack began to spread from where he touched it. 

"Oh no! Oh no! Oh no!" Dipper backed away was the crack spread further and further. Then the glass shattered, mist shrouded the room. Dipper made a break for the exit and heard laughter behind him.

"Run run run as fast as you can, I'll catch you boy!" The Shapeshifter shouted and Dipper rushed through the mist, he ran through the lab and eventually reached the elevator. The door shut before anything else could stop him.

Dipper raced out of the elevator screaming his head off. "MABEL! WENDY! SOOS!" Mabel and Soos ran into the gift shop.

"What's wrong bro-bro?" Mabel asked in a concerned tone.

"Yeah dude, you were screaming like crazy." Soos added.

"It-It's the Shapeshifter! It's back!" Dipper explained frantically, Wendy came down from the latter and Stan walked into the room as well.

"Shapeshifter? What is that?" Stan asked, everyone was silent and their eyes were wide. "Is it a band or something?"

COMMERCIAL

"Dipper, tell us what happened." Wendy ordered, glancing back at the vending machine.

"I-I was down in the basement and then something broke and the Shapeshifter was freed. Now he's down there." Dipper explained.

"Seriously what is the Shapeshifter?" Stan asked again.

"It's exactly what the name implies. It can turn into anything and anyone it sees." Dipper explained.

"Sounds like something Point Dexter would handle." Stan commented, meanwhile Wendy was working on pushing some displays of random animals glued together in front of the wending machine.

"Yes, we need Ford. He would know how to stop the Shapeshifter." Dipper agreed.

"Well then let's go find him bro-bro!" Mabel suggested.

"Hold on, just because there's some monster in the basement doesn't mean you kids can go near that alien." Stan reminded them, before Dipper could protest the door burst open and Ford and the alien walked in.

"Hello everyone, this is HSGUGE. HSGUGE this is my family and their friends." Ford introduced.

"That one looks like a large hairless gopher." HSGUGE commented, looking at Soos.

"Thanks dude." Soos gave a thumbs up, Ford then saw the vending machine was barricaded.

"What in the world is all this stuff doing in the way of the lab entrance?" Ford asked, walking over to it.

"We had to barricade the door because the Shapeshifter got out." Wendy explained.

"Why do you have a shapeshifter in you basement anyways?" Stan questioned.

"It escaped! Wait, how do you kids know about the Shapeshifter?"

"It attacked us last summer when we went into your bunker." Dipper explained.

"You went into that bunker!? That's besides the point, I thought I'd had it safely contained. I should've known it would've found a way to escape. Bu I didn't think anything of it when I went to bring it to my new lab!" Ford ranted.

"So my enemy is at free range? I suppose I have to terminate this town after all." HSGUGE decided.

"No need to do that! We still have him stuck in the basement!" Dipper said quickly.

"Yeah, let's freeze him again! Or better, turn him into ice cream!" Mabel suggested.

"There will be no need for any of that. I can stun him long enough for you to eliminate him." Ford told HSGUGE.

"Wait, so the Shapeshifter is your enemy?" Wendy asked and HSGUGE nodded.

"Indeed. Our races have been at war for a long time. We thought we had finally exterminated their race, but scans showed signs of one remaining descendant. Which is why I came here, alas my ship crashed due to its poor shape after a trip through an asteroid field." HSGUGE explained.

"Well then let's take this fool down!" Wendy shouted.

"Yeah, we can use attack glitter!" Mabel agreed.

"If I get to cause collateral damage I'm in!" Stan decided.

"Now now everyone, none of you are going in there. It will just be me and HSGUGE." Ford told them all. Before anyone could protest the vending machine door began shaking. Then it swung open and knocked down the barricade, revealing Dipper standing in the doorway.

"Huh, deja vu." Soos chuckled.

COMMERCIAL

"Shapeshifter! Nobody is falling for your tricks!" Ford shouted, everyone glared at the new Dipper.

"Guys its me! He's the fake!" New Dipper pointed at Old Dipper.

"No way that you're Dipper, there's no way he could knock down the barricade!" Mabel pointed out.

"Hey!" New Dipper protested.

"Uh yeah hey!" Old Dipper quickly yelled, which caused wavering looks across the group.

"Hm, perhaps we should do a questioning to see which is which. My ability to sense Shapeshifters is being prevented because of all the humans. And I would dislike unintentionally killing a human." HSGUGE suggested.

"I have a better idea, we force the Shapeshifter to change forms by attacking him!" Old Dipper shouted, he charged at New Dipper, weaving through hands trying to stop him.

"Stop Shapeshifter Dipper!" Ford yelled and the Shapeshifter pushed Dipper into the elevtor and followed him.

"ShapeDipper!" Mabel exclaimed, the doors closed as she jumped in to join the two Dippers.

"Drat! Curse my hatred of stairs!" Ford growled.

"Dudes the Shapeshifter is really dangerous, what's gonna happen to the twins?" Soos asked, everyone's expression displayed worry.

The elevator doors parted and the three tumbled out of it, all struggling with each other.

"Mabel let go of my arm!" Dipper #1 shouted.

"Don't let go, he's the Shapeshifter!" Dipper #2 told her.

"Now I know how Dipper felt when dealing with two Wendys." Mabel noted, unable to decide what to do.

"Oh yes, I remember that. Oh how close I was to tricking that boy!" Dipper #2 snarled and Mabel punched him in the gut, pulling Real Dipper away from him.

"You two think you can beat me? Then I shall destroy you!" The Shapeshifter vowed, and he transformed into Bill Cipher.

"Well well, good thing I spotted this little gem in the journal!" The Shapeshifter laughed, the twins backed away, eyes wide and mouths agape.

"Wow something must've happened involving whatever I am! I wonder what! But I do know one thing for sure, he's quite powerful!" The Shapeshifter rubbed his hands together excitedly. The elevator doors opened once more, and Soos, Wendy, HSGUGE, Ford,and Stan poured out of it.

"Th-that form! You have gone way to far Shapeshifter!" HSGUGE roared, firing a blue beam at him. However he just took the attack and didn't look bothered by it.

"Hm? What's wrong with this form HSGUGE? Whatever the case it doesn't matter. I'll see all you fools again one day. AHAHAHAHAHA!" The Shapeshifter cackled before vanishing in a flash of light.

"This is not good. He has Bill's powers." Ford stated.

"I must alert the SCLOP armada. That is our only chance at stopping him. I bid you all adieu." HSGUGE told them and he teleported away.

 "This is not good, it will take the Shapeshifter time to develop his powers. I must use that time to figure out a way to defeat him." Ford concluded.

"Let us help you!" Dipper told him.

"Yeah, we beat him once before!" Mabel added.

"No kids, there is no way I'm allowing you to partake in this. It is far too dangerous." Ford ordered.

"Me and my brother agree for once, no way you're getting involved. Now everyone out!" Stan pointed at the exit.

"Dipper, what do you think is going to happen?" Mabel asked on the way out.

"I'm not sure. But we managed to beat Bill, and this isn't Bill. So we can do this." Dipper told Mabel and she smiled at him.

"Thanks dip." Mabel thanked.

CREDITS

The Shapeshifter appeared deep in the Gravity Falls woods. 

"They seem pretty scared of this form. So I'll test out what it can really do!" The Shapeshifter decided.

"Maybe you could... Or perhaps you could donate your precious essence to us. We could use it for great things. A great fusion indeed." A voice whispered.

"Who said that?" The Shapeshifter asked, before suddenly four shadowy figured grabbed him and dragged him off.