Monster Falls

Monster Falls is an AU that alters all characters from their canon forms.

Dipper and Mabel find a magical stream, known as Fluvius Cantus, which turns them and everyone else in Gravity Falls into monsters that reflect their personalities.
 * Dipper morphs into a cervitaur (deer centaur).
 * Mabel has controversy over whether she's a mermaid or a unicorn. (There were more suggestions but these were the most prominent.)
 * Stan is a gargoyle.
 * Ford is a greek-style sphinx.
 * Wendy is a werefox, or, once or twice, a moth-person.
 * Soos is a clay golem.
 * Gideon is typically depicted as a vampire.
 * Pacifica is a gorgon or a unicorn (like Mabel!).
 * Robbie is usually depicted as a zombie.
 * Old Man McGucket is usually a scarecrow, warlock or a demon.
 * Melody is either a Harpie or a ghost.
 * Grenda is a Cecaelia (Half octopus half human).
 * Candy is a Kappa.
 * Waddles is a boar.
 * Bill is a humanoid hunter with a triangular head.

List of examples:

 * Stan as a gargoyle
 * Dipper as a cervitaur