Giffany

Griffany is the main antagonist of the Gravity Falls episode, Soos and the Real Girl.

History
When Giffany's game was being developed, the programmers noticed her obsessive tendencies and attempted to delete her. However, she retaliated and in return "deleted" them. The game made its way into stores, and three unfortunate individuals purchased and returned the game.

In Soos and the Real Girl, when Soos is looking for a way to help him talk to girls, he finds and buys her game. He immediately takes a liking to the simulation, despite him believing it not real, though he quickly becomes addicted to it and plays for thirteen hours straight, missing work at the Mystery Shack for the first time ever. Worried, Dipper and Mabel come to look for him. When they find him playing the game, they decide to take him to the mall to try to talk to real girls. However, Giffany follows him via power lines.

As Soos grows increasingly nervous in the face of real women, he is relieved to see Giffany, albeit slightly suspicious. He ignores this and decides to spend time with the simulation. After Soos meets and arranges a date with Melody, he attempts to "break up" with Giffany, who is infuriated by his actions. Soos promptly pauses her, which makes her even more angry, and leaves for his date with Melony with Giffany's CD with the intent of returning it. Unbeknownst to Soos, Giffany manages to leave her CD and follow him. At the restaurant, she projects herself onto numerous monitors and video games, and takes control of the Hoo-Ha's Jamboree there in hopes of ridding her of her competition. Soos does his best to defend his date and the twins, who have come to supervise. Giffany attempts to download Soos's brain to the game so they can be together forever but Soos manages to melt Giffany's game disc, thereby erasing her from existence.

Personality
At first, Giffany comes across as a friendly, innocent schoolgirl with little capacity for malice. However, her extreme obsessiveness quickly reveals this image to be a ploy as she grows more and more fixed on the player. She will do anything she can to keep the object of her affections with her at all times, as well as keep her at the center of his thoughts. When she sees potential competition, Giffany will employ a variety tactics to eliminate them. While her initial methods of badmouthing and manipulation are relatively tame, she will quickly descend into a homicidal rage if the perceived problem persists.

Abilities
Giffany is a sentient AI, and her most prominent ability is her power to override computer functions and transfer herself between electronics, including computers, toys, power lines, TV monitors, and more. She can easily weaponize machinery, able to utilize everything from Hoo-Ha's Jamboree to skeeball games. She opens and closes several doors using her power. She can download a person's conscious mind into the digital world, thereby uniting that individual with her forever. However, she cannot exist without her game disc.