Once Upon a Swine

At the moment when Mabel wins Waddles the pig at the Mystery Fair, Dipper ruins his chance to impress Wendy. But when Dipper finds a way to travel back in time and changes his fate with Wendy, Mabel's fate also changes--for the worse. Then, when a prehistoric creature snatches up Waddles, it's up to the Gravity Falls gang to save him!