Role-Reversal
Dipper ran into the Corduroy cabin, out of breath. He knew Wendy's family was out for the weekend and that she had no problem with him coming in. The thirteen year-old boy rushedly knocked on her door.
"Come in!" he heard his girlfriend call from inside. He opened the door. Wendy noticed immediately that Dipper was in a panic. His eyes were widened, he was out of breath and she could see sweat dripping from under her, well, techincally now his, aviator hat. "Dipper, what's wrong?!" she asked, concerned, jumping up from her bed, where she'd been sitting and snatching her hatchet from her nightstand.
"No, calm down...there's...there's nothing chasing me," the younger boy replied, between breaths. It was completely normal for some type of creature to be on his trail. Wendy lay the weapon back on her nightstand and relaxed her posture slightly. She was still worried about why her boyfriend had just run, assumingly, all the way from the Mystery Shack.
"I-I'm not really sure how to e-explain it," Dipper said.
"Dipper, we've been through the apocalypse together, I'm pretty sure, whatever this is, I can handle it," the ginger replied.
"Uh, okay," Dipper said. He gaze averted to his right and his hand found it way to the back of his neck, rubbing it, nervously. "Uh, Wendy, y-you-you're p-pregnant."
"Wait, wait, wait, wait, wait, what?!" Wendy stuttered, unable to entirely comprehend what she'd just heard. "How...How would you even know that?!"
"Long story," Dipper told her, and with him, it usually was. Dipper went over to the bed and sat down. Wendy sat down beside him. Then, the flustered boy explained what was going on.
Flashback
Dipper walked into the living room of the shack. Everything was normal except for the man standing in the center of the room patting down flames on his grey coveralls.
"Hot! Hot!" he exclaimed.
"Blendin?" Dipper asked.
"Oh, D-Dipper!" Blendin exclaimed, not expecting to see the teen boy standing behind him.
"What are you doing here?" he asked the time traveller.
"I-I-I was j-just stopping s-some t-time anomalies," he explained. "O-one of o-our time officers w-went t-time r-rogue."
"Oh, okay... so why are you in the shack?" Dipper questioned.
"I-I'm not sure," Blendin replied, scratching his head. "I-I-I think there's s-something wr-wrong with th-th-the t-time machine." He pulled the measuring tape-like object from his tool belt.
"Do you want me to see if Grunkle Ford and I can fix it?" Dipper offered.
"W-w-well, I'm n-not supposed t-to let other p-people t-t-touch it," Blendin hesitated.
"Don't worry, it's in good hands," Dipper said.
"W-well...o-okay then," Blendin agreed, reluctantly handing over the device to the younger boy. "B-be careful."
"Don't worry," Dipper said. "It'll be fine."
End of Flashback
"So then I went down to Great-Uncle Ford's lab and fixed the time machine, there wasn't really that much wrong with it just-" Dipper continued his story before Wendy cut him off.
"So, wait, how does this lead to you knowing that I'm, you know, p-pregnant," Wendy asked, still a little nervous. "I mean, is it definite? Like, how do you know? We're to young to be parents, I'll only be seventeen and you'll only be fourteen when the baby is born! Are you sure it's true, or a-am I freaking out over nothing?!"
"I'm postive," Dipper said, starting to get nervous because he hadn't really thought about it. "J-just let me finish the story."
Flashback
Dipper finished screwing the back onto the time machine, his turned it over and over in his hands looking at it. Blendin wasn't due back from fixing the time anomalies for at least another twenty minutes. Maybe I should test it. Dipper thought. Hmm, what's something I've wanted to know for a long time? Maybe where I'm going to spend next Christmas. Dipper and Mabel had spent last Christmas in Piedmont with their parents. They'd wanted to spend it at the Mystery Shack with all their family and friends, but they never got to. Dipper was now curious as to where he and his sister would be spending their next Christmas. It was only March yet, but he didn't think it mattered, you can never know something too soon. He pulled the tape out to nine months and one day, as it was March 24th. He shut his eyes and soon he was standing in a slightly different version of the same lab. Well, I guess it worked, I'm not somewhere in the middle of nowhere. He quietly took the elevator up to the main floor of the shack. He went up the stairs with out a sound and slipped out into the gift shop. It was empty. He could see the snow coming down hard outside.
"Open mine next!" he heard his sister's eager voice from the living room. Well I guess that answers my question. Dipper crept over to the door into the living room, peering inside. He saw himself, Mabel, Stan, Ford, Wendy, Soos, Melody and his parents all inside, sitting around the Christmas Tree. Then he noticed something when Wendy shifted her position, she was holding something, a baby? Did Soos and Melody have a baby? Then he noticed his slightly older self go over to where Wendy was sitting with the baby in her arms. He had a small gift in his hand.
"Do you want to see what Daddy got you?" he heard himself ask the baby. Wait, if this was Soos' baby, shouldn't he be the one giving the gift to the baby? Dipper looked puzzled at the situation. He continued watching. "Look, buddy! Daddy got you a new stuffed multi-bear! The toy he removed from the wrapping was like a regular teddy bear, but had many more heads than usual.
"Do you like what your Daddy got you?" Wendy asked. Future-Dipper lay the toy next to the baby in Wendy's arms.
"Kid, are you trying to spoil your son with nerd stuff already?" Stan complained. "He's only a few days old!" Wait, my son?! Dipper thought. That can't be right, I'm only fourteen here! He double checked the time machine to make sure that the time he'd jumped to was correct. Yeah, nine months and... wait... nine months?! Wendy's pregnant...now?! He had to clap a hand over his mouth to keep himself from freaking out. Instead, a small squeak escaped the young boy.
"Did anyone hear that?" Ford asked.
"Hear what?" Future-Dipper asked, slightly abruptly. "I didn't hear anything!" Dipper realized that his future self was covering for him. Then he noticed future him turn towards the doorway, winking and mouthing: good luck!
Dipper pulled out the tape set to the present and let it go, zapping himself back to when he left, before running out the door to the Corduroy cabin.
End of Flashback
"So, we're gonna have a son?" Wendy asked.
"Yeah," Dipper said.
"Well, it's kind of a switch, the boy telling the girl she's pregnant," Wendy laughed, trying to lighten the tense mood in the room.
"Yeah," Dipper smiled, before kissing his girlfriend.