Fairies are small, winged, mythical creatures.
History
Season 1
One appears during a flashback in "Land Before Swine." Dipper and Mabel briefly see a pink fairy outside their bedroom window before Soos squashes it with a flyswatter.
In "Gideon Rises," Dipper mentions a "Barf Fairy" when consulting Journal 3 on how to get the Mystery Shack back from Gideon.
Season 2
In "Dungeons, Dungeons, and More Dungeons" while walking through the forest with Mabel and Grenda to save Dipper and Ford, Stan squishes a fairy that was biting him.
It is revealed in "The Last Mabelcorn" that fairy dust can be used to knock out unicorns. The Fairy Nail Salon is located in the enchanted part of the forest.
In "Weirdmageddon 3: Take Back The Falls," a fairy is among the creatures of Gravity Falls waving off Dipper and Mabel as they leave town.
Appearance
Fairies are small, winged, humanoid creatures that often glow with a colorful aura.
The fairy Dipper and Mabel see in "Land Before Swine" has long hair, a short dress, bare feet, and a pink aura. The fairy that Stan smacks in "Dungeons, Dungeons, and More Dungeons" is blonde, has a blue dress, blue flats, and a light purple aura.
Trivia
- In the episode "Dungeons, Dungeons and More Dungeons", the fairy that was biting Stan appears to be a reference to Navi from The Legend of Zelda: Ocarina of Time.