Gideon Charles Gleeful, better known as his stage name, Li'l Gideon is the yandere to Mabel Pines from Gravity Falls.
He desires Mabel Pines.
Gideon is a fraudulent child psychic, whose hunger for ultimate power motivates him to manipulate and intimidate others into giving him what he wants.
He uses his adorable charm to fool people into thinking he's just some innocent kid. When he starts a "relationship" with Mabel, he makes sure to make it a public display, making it difficult for her to turn him down. On multiple occasions, he's attempted to kill Dipper, Mabel's twin brother, because he believes that he has tried to come between Gideon's relationship with Mabel.