Dipper and Mabel vs. the Future

"" is the 17th episode of the second season of Gravity Falls, and the thirty-seventh overall. It premiered on October 12, 2015.

Official overview
Mabel decides to plan for her and Dipper's 13th birthday party. Meanwhile, Dipper ventures below the town to find its most shocking secret.

Synopsis
Stanford tells Dipper that the Rift is cracking, and the only way they could fix it is from a UFO that landed in Gravity Falls millions of years ago.

Credits

 * Written by:
 * Matt Chapman
 * Josh Weinstein
 * Alex Hirsch


 * Outline by:
 * Mark Rizzo
 * Alex Hirsch


 * Directed by:
 * Stephen Sandoval


 * Storyboarded by:
 * Ben Holm
 * Dana Terrace
 * Luke Weber


 * Additional Written Material by:
 * Jeff Rowe


 * With the Voice Talents of
 * Kristen Schaal as Mabel
 * Jason Ritter as Dipper
 * Alex Hirsch as Grunkle Stan, Soos, and Bill
 * Justin Roiland as Blendin Blandin
 * Linda Cardellini as Wendy
 * J.K. Simmons as Ford
 * Niki Yang as Candy
 * Carl Faruolo as Grenda
 * Dee Bradley Baker as Sprott


 * Casting by:
 * Sara Jane Sherman

Character revelations

 * Dipper and Mabel were born on August 31, 1999, which places the series' setting in 2012, the year the series premiered.
 * When they were younger, Mabel used to glue the googly eyes to her chin and talk as Mr. Upside-downington, but she hasn't done that since third grade.
 * Ford has 12 Ph.Ds.

Series continuity

 * Grenda's pet iguana, which first appears in "Double Dipper," makes an appearance.
 * On Mabel's miniature Mystery Shack there is a banner that reads, "Sev'ral Timez."
 * Mabel's scrapbook of "Summer Memories," which is first seen in "Dipper vs. Manliness" and later shown in "Society of the Blind Eye," makes an appearance.
 * Tyler Cutebiker is shown as Gravity Falls' mayor after winning the election in "The Stanchurian Candidate."
 * Stan's fishing hat that he made for Mabel from "The Legend of the Gobblewonker," can be seen on Mabel's bedpost.
 * During the cold open, next to the calendar in the twins' room is a picture of Mabel and Waddles from "Land Before Swine."
 * The UFO key chain seen in "The Hide-Behind" and "Dungeons, Dungeons, and More Dungeons" makes an appearance.
 * Grenda is dating Marius.
 * Bill Cipher possesses Blendin Blandin, who was one of Bill's "options" to possess, as seen in "The Last Mabelcorn."
 * Near the end of the episode, Mabel goes to what she calls "Sweater Town" just like she did in "The Hand That Rocks the Mabel."

Cryptograms

 * The cryptogram in the episode's credits reads, "ETX CPI ASTD GI?" Once decoded using the Vignère key BLUEBOOK, it reads "DID YOU MISS ME?"
 * The cryptogram in the episode's end page reads, "4-16-19 8-6-9-8-16-19-21-25 5-19-19-11-19-20 18-23-6 23-1-23-25 22-3-4 18-15-10-23-12-12-25 1-19'2-19 6-19-23-21-16-19-20 4-16-19 20-23-25 17-15-2-19 3-8 4-16-19 8-23-5-4. 19-11-22-6-23-21-19 4-16-19 5-4-6-23-10-17-19. 19-2-19-6-25-4-16-15-10-17 25-9-3 21-23-6-19 23-22-9-3-4 1-15-12-12 21-16-23-10-17-19." Once decoded using the combined cipher it reads, "THE PROPHECY SEEMED FAR AWAY, BUT FINALLY WE'VE REACHED THE DAY, GIVE UP THE PAST. EMBRACE THE STRANGE. EVERYTHING YOU CARE ABOUT WILL CHANGE."
 * The symbols inside the UFO (that Dipper took a selfie with) are written in Bill's symbol substitution cipher. (Semicolon indicates line break)
 * In black writing: probability drive engine; probe atorium; blerg bloth and beyond; used thatens half price
 * In brown writing: specimen has; escaped; is changing; forms