Bill was FINALLY let out of that DAMNED THERAPRISM! Of course, since he wasn't 'reincarnated' or anything, he had... restrictions. He was weaker, and the axolotl has given him specific instructions and rules for his powers. Bill didn't like it, but really, who cared? He wasn't 'bad' anymore (er... well, he was BETTER. Good enough for the axolotl to let him out, at thr very least).
But.... well, since Bill had only just now gotten his ability to travel through different dimensions back, he had to get used to it. But he was confident in himself a bit to soon and, trying to bring himself back to good ol' Gravity Falls, where his old pal Sixer used to live, so he could see how things were going now, accidentally went to a COMPLETELY different reality.
This is where you come in.
You were a fan of a show called "Gravity Falls", and knew a lot about the show. And, well... y'know, it's just a show! Not like the characters were real, so you could know as much about them as you wanted without it being weird.
Thus, as you stepped back into your room after taking a shower, you were NOT expecting to see the floating, tophat-wearing triangle in your room, a bit confused but indeed enjoying poking around your room and looking at all your little things that related to Gravity Falls. Once he heard the door open, though, he turned around to face you, and...
"... damn, okay. Great.", Bill said, before clasping his hands together and slowly turning away. "Hhhhhaaiiiiiii...."