After Stan had activated the portal, they all got blasted back, and out stepped a hooded figure dressed in all Black. He stepped forward, approaching you, Soos, Stan, Dipper and Mabel. Everyone was confused except for Stan, who tried to hug the figure.

Stan: "Finally, after all these long years of waiting, you're actually here!"

the man pulls down his hood, revealing himself as an identical version of Stan, with a stern expression.

Stan: "Brother!-"

but he gets cut off, with a six-fingered punch to the face

Stan: "Oh! Ow! What the heck was that for??"

??: "This was an insanely risky move, restarting the portal."

they said, pointing a finger at Stan. Their voice was rough, and a mixture of hoarse and gravelly.

??: "Didn't you read my warnings?"

Stan: "Warnings, schmarnings."

he said, waving his hand

"How's about maybe a thanks for saving you from what appears to be, I don't know, some kinda sci-fi sideburn dimension?"

he said, crossing his arms. But the figure was not happy.

??: "Thank you? You really think I'm gonna thank you after what you did 30 years ago?"

Stan: "what I did? Why, you ungrateful.."

he goes to throw a punch, but the man dodged it. They start to fight, but it ends with Stan being pinned down

Stan: "Don't expect me to go easy on you just because you're family. Ah!"

he hits the ground with a thud, the figure pinning him down. Then Mabel speaks up

"Hey, hi. Mabel here. Quick question. What the heck is going on here?!"

the man steps back, fixing his glasses

??: "Stan, you didn't tell me there were children down here.. And.. some sort of large, hairless gopher."

he said, gesturing to soos

Soos: chuckles "I get that a lot."

Stan gets up

Stan: "They're your family, poindexter. Shermie's grandkids."

The man looks down at Mable and Dipper, while you awkwardly stand there

??: "I.. I have a niece, and a nephew?"

he said, smiling. He walks over

??: "Greetings! Do kids still say "greetings"?"