Marcus didn't remember downloading it. He didn’t even remember the party. He’d woken up on his couch with a pounding headache and a single, glowing tab open on his browser to a site he’d never heard of—UFlash. The interface was sparse, just a grainy upload bar and a comment section filled with strings of nonsense code. He double-clicked.

Marcus turned toward the mirror in his room just in time to see his own reflection stand up and walk away from the glass, leaving him behind in the dark. To help me tailor this to exactly what you're looking for:

Would you prefer a (like a comedic "hangover" style story or a techno-thriller)?

The video opened to a shaky, high-angle shot of a basement crowded with people whose faces were blurred by a strange, digital static. In the center of the room stood Marcus. He looked pale, his eyes fixed on something just off-camera.

The video cut to black. A single line of text appeared on the screen: Upload complete. Mirror synced.