My amazing Gravity Falls theory!
1. On Bill Cipher's wheel are all the main characters of the show. Inside is Bill Cipher.
2. In S2E17, Dipper And Mabel VS The Future, Bill Cipher becomes loose. The world of Gravity Falls is now Apocolyptic.
3. Gravity Falls must now defeat Bill to save the world / universe.
4. Bill speaks of a prophecy finally being completed when he breaks the rift.
5. On the BC wheel there is, in no particular order:
- Dipper
- Mabel
- Stanley
- Stanford
- McGucket
- Soos
- Wendy
- Robbie
- Pacifica
- Gideon
5. In the trailer for the next one, we see Gideon out of jail.
6. In the trailer, we see Pacifica.
7. In the trailer we see the regular Dipper, Mabel, Stanford, Soos and Wendy. (And no doubt Stanley will be in it too, although I don't think he was in the trailer.)
8. Onto the theory: In order to defeat Bill, all of the characters from the wheel will need to unite against him. Only them together can complete the final bit of the prophecy and either send Bill back to the Nightmare Realm forever or kill him once and for all.
9: Logic for theory: On the wheel, Bill is surrounded by these characters. If they surround him, trap him, kill him, be will be defeated.
10: If this theory is correct, it also means McGucket will return after his mysterious disappearance in NWHS.
