.GIFfany (or Giffany) is an antagonist from Gravity Falls and Yandere of Soos.
Giffany is featured in the Gravity Falls episode, "Soos and the Real Girl". She is a parody of girls from Japanese dating sim games. She was created to be the perfect girl, but her creators somehow made her sentient. When they tried to delete her, she retaliated and killed them instead. Due to her clingy and obsessive nature, she became overly attached to her players, believing them to be her boyfriend. Her behavior scared the players so much that they returned the game just to get away from her.
Giffany tends to become attached to whoever plays her game, genuinely believing that the player is her boyfriend or best friend. She acts nice towards her boyfriends and best friends. When he or she isn't spending time interacting with her through the game, she follows her "boyfriend" through electronic devices. When the device she is in is destroyed, she instantly teleports into the nearest device. When Soos breaks up with her, she goes into a jealous fit and declares that she loves him more than anyone and that she won’t let anyone take him away from her. To ensure they “stay together”, she corners him at a pizzeria where his date with Melody took place and proposes that he be downloaded into her game or be forced to watch his friends and Melody be killed