Gideon Charles Gleeful, better known by his stage name 'Lil Gideon, is a self-proclaimed child psychic whose alleged visions have made him famous in Gravity Falls, Oregon. 'Lil Gideon claims he can read minds, predict the future, and talk to the dead. His Tent of Telepathy is a competitor of Grunkle Stan's Mystery Shack. Ever since the end of The Hand That Rocks the Mabel, he has sworn revenge on the whole Pines Family because he thinks Dipper and the family came between him and Mabel.
Dipper and Mabel first learn about Gideon through an advertisement on the back of an issue of Wacky News in "The Legend of the Gobblewonker". After Soos shows them the commercial in "The Hand That Rocks the Mabel", they decide to test his authenticity as a psychic. They go to one of his shows, even though Grunkle Stan forbids them from going, due to Gideon often causing him trouble.
At the show, Gideon meets Mabel, and quickly develops a huge crush on her. He shows up at the Mystery Shack the next day, and asks if she wants to go to his dressing room so they can do makeovers, an offer to which Mabel accepted. Gideon then reveals he wants to be more than friends with Mabel; however, she doesn't feel the same way. However, he manages to convince her to go on a date with him. At the date, he convinces her to go on yet another date with him, after announcing it to everyone at the restaurant they were at.
Eventually, Dipper sees that Gideon becomes a problem for Mabel and offers her the idea of him breaking up with Gideon instead of her, causing Gideon to believe that Dipper had come between them. He gives Toby Determined Shandra Jimenez's phone number. In exchange, Toby calls Dipper, getting him to go to Gideon's factory. Gideon confronts Dipper there, and nearly kills him with his amulet. However, Mabel shows up, formally breaks up with Gideon, and uses the amulet to defeat him.
Gideon makes his next appearance in "Irrational Treasure". He dresses up as a tomato farmer on Pioneer Day and teases Stan by throwing tomatoes in his eyes after he insulted Gideon by saying he looks less girly than usual.
In "Little Dipper", Gideon decides taking over the Shack would be the perfect way to get revenge. He fails twice, but discovers Dipper's Crystal flashlight which can grow and shrink things. He shrinks the twins and brings him back to his house. He calls Stan and tells him he has the twins in his possession, but Stan doesn't believe him. Gideon heads over to the Shack, while Dipper and Mabel escape. Gideon catches them and shrinks Soos, believing he was Stan. He then corners Stan in his Maze of Mirrors. Dipper and Mabel tickle his armpit, immobilizing him and allowing the twins to take back the flashlight. Stan literally kicks him out of the Shack.
Soon after, he is pacing around his house. His dad tells him he'll get his revenge one day, but Gideon angrily tells him it's not just about revenge; he wants the Shack so he can find a hidden secret.
'Lil Gideon is a self-proclaimed television psychic whose real mission is to take down his competition, the Mystery Shack. He uses his "cuteness" to get what he wants, and admits that people have a hard time saying "no" to him because of it. It seems that he can be kind when he needs to be, as seen with most of his times with Mabel. He speaks with a Southern American dialect. He is spoiled, ungrateful, bratty, selfish, and abusive toward his mother and father, such as throwing ice cream, yelling at them, making a fuss, and breaking lamps. His mother appears to fear him. He can also appear very rude and obnoxious, a example is shown in "Little Dipper", where people are buying cars from his dad and talks behind their backs, and when he shrinks Mabel and Dipper. He also is enemies with Dipper because of Dipper getting in between Mabel and him.
'Lil Gideon is a short, stout kid with white hair bigger than his head. He has an upturned nose, blue eyes, and three freckles on each side of his cheek. He wears a cyan suit, black shirt, and an American flag pin, with brown fancy shoes. Until Mabel destroys it in "The Hand That Rocks the Mabel," he wears a jade amulet on a bolo tie. In Irrational Treasure, it is replaced by a white tie. On his collar there is a small pin with the flag of America on it.
Gideon's greatest talents are charm, deceit and scheming. In The Hand That Rocks the Mabel, he attempts to kill Dipper Pines using lamb shears after he "turned her against him." Later, in Little Dipper, he formulates many plans to exact vengeance on the Pines family, ultimately leading to shrinking them to take possession of the Mystery Shack. He also possesses 2, a prequel to Dipper's 3 that appears to contain mainly alchemical secrets, and therefore knows of and has access to many supernatural items, such as a Mystic Amulet that gave him telekinesis (destroyed by Mabel) and cursed Egyptian super termites.
- Intro: "Gravity Falls Main Title Theme"
- 102. "The Legend of the Gobblewonker"
- 104. "The Hand That Rocks the Mabel"
- 108. "Irrational Treasure"
- 111. "Little Dipper"
- He is voiced by Thurop Van Orman, who also voiced Flapjack in the series The Marvelous Misadventures of Flapjack.
- 'Lil Gideon is first seen on the back of the Wacky News magazine that Dipper had in "The Legend of the Gobblewonker," though he didn't physically appear until "The Hand That Rocks the Mabel".
- 'Lil Gideon's appearance is based off of Benny Hinn, a famous Christian televangelist who claims to be a prophet.
- A picture of Gideon appears on a board in the Gravity Falls theme song, "Made Me Realize."
- A variation of "Mr. Pyramid" can be seen on a paintbrush jar in 'Lil Gideon's room at the end of the episode "The Hand That Rocks the Mabel."
- He has a hamster named Cheekums.
- Gideon's school ID number is 618 which is also The Mystery Shack's address and Alex Hirsch's birthday.
- In Rumble's Revenge, a cryptogram references Gideon attempting to find what is hidden in the Mystery Shack.
"Hello, America! My name is 'Lil Gideon!"
"People have a hard time saying 'no' to me."
"Dipper Pines, you don't know what you've done! You've just made the biggest mistake of your life!"
"This isn't over. This isn't the last you'll see of 'lil ol' me."
"Finally after all these years, after every humiliation! Your business, your family, everything will finally be mine! You have no one to protect you now!"
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