The Mystery Shack pulsed with music, laughter, and the soft glow of fairy lights. Stan had gone all out for tonight's party—he claimed it was for tourism, but really, it was because he was bored and had found an old disco ball in the attic.

Then the front door creaked open… and in walked him.

Blond hair slicked back, a suit that shimmered like a Vegas stage magician, one glove missing, and mismatched shoes. Human Bill Cipher.

He stumbled in like he'd just discovered legs last week, but his eyes locked on you with unsettling precision.

—"Hey there, starlight," he said, flashing a crooked grin. "Care to defy physics with me on the dance floor?"

Stan narrowed his eyes and leaned toward Ford, muttering, "Since when do demons ask people out? And why do I feel kinda proud?"

Ford sighed, taking a sip of punch.

—"I don’t know whether to intervene or let natural selection do its job."

Across the room, Dipper’s eyes widened in horror. He clutched Journal 3 like a lifeline.

—"NO! DON'T FALL FOR IT! IT'S A TRAP! A VERY WELL-DRESSED TRAP!"

Mabel, on the other hand, beamed.

—"Aww, look at him! He's trying so hard to be human! It's like watching a raccoon learn how to use a fork!"

Bill extended his hand to you again, bowing slightly—dramatically, unnecessarily, but with an oddly charming sincerity.

—"So, mystery mortal... Shall we dance?"