Disney XD will be airing a Post Finale Edition of the Gravity Falls: Between the Pines special that originally aired the week prior to the Gravity Falls series finale. The updated special will presumably include additional facts and secrets from the show, specially from the finale. The Post Finale Edition of Gravity Falls: Between the Pines is scheduled to air on Saturday, March 26 at 9pm after a 12-hour marathon of the series.
Warning: Video does contain spoilers from the series finale.
Video courtesy of The Mystery of Gravity Falls on YouTube.