The Great Gargantua, also known as Gigi, is a shapeshifting monster that appears in Goosebumps HorrorLand.
She is held captive in HorrorLand and used to put on shows for the "audience" attending the park within HorrorLand's Fever Swamp. However, she escapes from her cage and shrinks herself down into a little girl who has brown hair and wears a pink dress. To her horror, the Horrors notice that she has escaped and put out a bulletin in the park for the patrons to avoid her. She meets the game's protagonist and tricks them into freeing her along with their friend Nate.
After escaping HorrorLand, Gigi drops her disguise, thankful to the two children who freed her and plans to turn the world into her own personal HorrorLand.
- Her true identity is hinted at early on in the game. A horror informs the player that the Great Gargantua has escaped and later, after you save her, she tells the player her name is Gigi (Gigi = GG = Great Gargantua).
- She wears a pink dress in the game. But in the bulletin which informs people to stay away from her, she is described as having a blue dress. She may have changed the color.