Lil' Gideon is a child psychic and self-promoter of his own tourist trap, the Tent of Telepathy. He's adorable but has a dark side.
Li'l 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 he admits that people have a hard time saying "no" to him because of it. It seems that he can be kind and charming 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, selfish, and abusive toward his mother and father, such as throwing ice cream, yelling at them, and breaking lamps. Even shown as an infant, he still gets what he wants. His mother appears to fear him. He can also appear very rude and obnoxious, an example is shown in "Little Dipper", where people are buying cars from his dad and talks behind their backs, when he shrinks Mabel and Dipper.
Li'l Gideon is a stout kid who acts much older than he seems. His appearance best resembles a pig. During most of the series he wears a baby blue suit, black shirt, an American flag pin, brown fancy shoes, and a green amulet. When he touches this amulet it glows and gives him special powers. It is later discovered that this amulet is featured in Journal 2. After Mabel destroys it in "The Hand That Rocks the Mabel," it is replaced with a white tie.
Gideon's greatest talents are charm, deceit, and scheming. In "The Hand That Rocks the Mabel," he begins dating Mabel, against her will, after seeing her in the audience of one of his performances. Unable to end the relationship, Mabel sends Dipper to tell Gideon "It's over," but Gideon takes it badly, screaming that Dipper had "turned her against him." He attempts to kill Dipper using his amulet, but is stopped by Mabel, who destroys the amulet, thus eliminating Gideon's powers.
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.
Role in the series
Dipper and Mabel first learned about Gideon through his TV commercial and they wanted to test his authenticity as a psychic. They went to one of his shows even though Grunkle Stan forbade them from going due to Gideon 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 her if she wants to go to his dressing room so they can do makeovers on each other, an offer Mabel accepted. Gideon then reveals he wants to be more than friends with Mabel; however, she doesn't feel the same way. 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 dining at. Mabel really didn't want to, but many people put pressure on her and she gives in to him.
Dipper sees that Gideon has become a problem for Mabel and offers her the idea of him breaking up with Gideon instead of her, causing Gideon to believe that Dipper has come between them. Gideon gives Toby Determined Shandra Jimenez's phone number. In exchange, Toby calls Dipper, telling him to go to Gideon's factory. Gideon confronts Dipper there, and nearly kills him with his amulet. However, Mabel shows up, to tell Gideon that she just wants to be friends, and she sees Gideon trying to kill Dipper. Mabel then formally breaks up with Gideon, and uses the amulet to defeat him. Gideon is then seen leaving the forest saying "this isn't the last you'll see of little ol me." Afterwards, he creates a little playset of the Mystery Shack, planning revenge. It is then shown that he owns book 2.
Gideon makes his next appearance in "Irrational Treasure". He dresses up as a tomato farmer on Pioneer Day and teases Stan by throwing tomatoes at his eyes after Stan insulted Gideon by saying he looks less girly than usual.
In "Little Dipper", Gideon is playing with his Mystery Shack set, and decides that taking over the Shack would be the perfect way to get revenge. He first tries to get Stan to sign over the Mystery Shack, but Stan is not fooled. He tries to set termites on the Shack, but Stan smashes the jar and the termites go after Gideon's bat and his hair instead. After failing twice, Gideon discovers Dipper's Crystal flashlight, which can grow and shrink things. He shrinks the twins and brings them 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 again and shrinks Soos, believing he was Stan. He then corners Stan in the Maze of Mirrors. Dipper and Mabel tickle his armpit, immobilizing him and allowing the twins to take back the flashlight. Stan then literally kicks Gideon out of the Shack. Soon after, he is paces around his house. His dad tells him he'll get his revenge one day, but Gideon angrily tells his dad that it's not just about revenge; he wants the Shack so he can find something.
In "Dreamscaperers", Gideon summons a mind demon by the name of Bill Cipher to enter Stan's mind in order to retrieve the code to a safe holding the deed to Mystery Shack. His plan fails, so Gideon resorts to Plan B; dynamite. He blows up the safe, takes the deed and uses a wrecking ball to destroy the Mystery Shack.
Gideon plays a prominent role in the season finale, "Gideon Rises". He reveals the purpose of the journals, and tells his father (and the viewing audience) that he still requires the other one, 1. Upon stealing 3, however, he pursues the Pines twins (who were forced to leave town around this time) in a giant robot. He catches them and attempts to reclaim Mabel as his bride and almost succeeds. He is stopped at the last moment by Dipper, however, and the robot crashes after a brief skirmish in the control center. He attempts to have the Pines twins arrested, but Stan reveals the falsehood of Gideon's supposed powers: his special pins are hidden cameras. The scorned townsfolk turn on Gideon and arrest him, but not before Stan reclaims his deed and steals 2 from Gideon.
When Bud Gleeful runs for mayor in "the Stanchurian Candidate," it is revealed that Gideon is controlling his father from the County Jail, using a spell he found in Journal 2. However, Bud loses the election, and Gideon is furious. He eventually accepts this as a minor setback, knowing that Bill Cipher will return to Gravity Falls and free him.
Shortly after his first encounter with Mabel, Gideon fell head over heels for her, and continually attempts to get Mabel to return the feeling through various schemes, but to no avail. Despite his crush, Gideon seeks revenge on Mabel and her family (whom he views as the only thing standing between a successful relationship). Mabel, on the other hand, finds Gideon to be creepy and unattractive, not to mention totally evil, and despises him and every attempt he makes to enact his vengeance.
Gideon and Dipper are mortal enemies, and are frequently in combat. Gideon sees Dipper and the rest of his family as a threat to be dealt with, so as to get revenge, win Mabel's love, and seize control of the Mystery Shack and its secrets. Thus, he spends his free time plotting and executing complex schemes, none of which succeed. At the same time, Dipper dislikes Gideon just as much and is the frequent victim and stopper of his young enemy's evil plans.
For unknown reasons, a rivalry has existed between Stan and Gideon for years. Business rivals to begin with, their rather competitive personalities fuel their feud further. Gideon wishes to eliminate Stan for numerous reasons, namely to take control of his business and a strange secret it possesses and to remove the "obstacle" to winning Mabel's affection, and he plots day and night to figure out a means of revenge, though he is sometimes satisfied with simply irritating Stan. Stan doubts Gideon's abilities and constantly teases him.
Though a father traditionally has authority of his son, Gideon's and Bud's situation seems to be the complete opposite: Gideon bosses Bud around and Bud submits without a second thought. While Gideon just utilizes his father as a tool to help him reach his goals, Bud nonetheless loves his son and is willing to do much for him, seeing the boy as "precious." However, even his father, at least in the newspapers, said that "He could've used a time-out."
Due to her son's sinister and intimidating nature, Mrs. Gleeful is submissive to Gideon and fears him, trembling at the mere sight of the young boy. Gideon lacks respect for her and treats her abusively.
- Gideon is Hebrew for “destroyer” or “feller of trees”, which is fitting considering his arch-nemeses are the Pines family and one of the villains of the show.
- Li'l 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".
- Li'l Gideon's appearance is based on 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.
- A variation of Bill Cipher can be seen on a paintbrush jar in Li'l Gideon's room at the end of the episode "The Hand That Rocks the Mabel."
- 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 searching for an object of some sort.
- Gideon's name is a pun on "giddy and gleeful".
- His relatioship between Gideon and Stan is similiar to relationships between Plankton and Mr. Krabs.