Lydia made her debut in the episode "Control Freaks". She, alongside the other ghosts under Freakshow's control, performs several acts at Circus Gothica, while committing crimes as well. Unlike the other ghosts, she serves Freakshow willingly even without the Crystal Ball Staff, and does not abandon him when the Staff Breaks.
She first appears robbing a jewelry store alongside her fellow ghosts. Danny attempts to stop them, and begins to fight, but the ghosts flee when the police came, making it seems as if Danny was robbing the place.
Later, she is seen fleeing after presumably robbing a bank along with the other ghosts. Danny chased after them, but eventually lost them. Leading him to the opening ceremony of Circus Gothica, where she performs disguised as a human.
Eventually Freakshow gain control of Danny, and he assisted with the ghosts crimes. While Freakshow and Danny hold Sam and Tucker off, Lydia attacks the parents of Amity Park, who were invited by Freakshow for a free show, with her tattoos. However, she was defeated by Jack and Maddie Fenton.
Lydia later returns in "Reality Trip" as the secondary antagonist. She was first shown captured by the Guys in White in order to get Freakshow to tell them about the Reality Gauntlet and its Reality Gems. However, when they freed Freakshow, he manages to quickly defeat the Guys in White and free Lydia, they then escape from their prison.
She later attacks the students of Amity Park's high school at the Dumpty Humpty concert. Her bat tattoos kidnaps Sam and Tucker and brought them to Freakshow, but was saved by Danny. Before Danny can defeat Freakshow, Lydia came to his assistance, and they fled using a flying train.
They later return to the Dumpty Humpty concert, and Lydia took Sam and Tucker hostage. While Danny and Freakshow fight, Tucker eventually free him and Sam from her by pulling her hood over her head, sending her flying into a sign.
When Danny and his friends accidentally press the gems of the Reality Gauntlet in the right order, Freakshow became the ringmaster of all reality. But as Danny and his friends were still holding on to the Gauntlet, they had as much of control as he did. They quickly think of a place to hide their respective gems, causing the Gauntlet to lose its powers. With the gems gone, Freakshow and Lydia were forced to flee.
Lydia later kidnaps their parents in order to force them to find the gem. Lydia assigns one of her bats to spy on Danny and his friends on his process. When they finally found all three gems, they were immediately taken to Freakshow by Lydia.
She steals the gems from Danny and tied them up using her tattoos. Freakshow activates the Reality Gauntlet, making him the Ringmaster of all reality. However, when Freakshow turned into a ghost and was sucked into the Fenton Thermos, an angry Lydia attacks Danny, but quickly flees when he turns her into various objects.
Her final appearances was in "Planet Phantom". She was first seen as one of the various ghosts to surround and attack Danny. She later appears to turn the Planet intangible so the Disateroid would pass through it.
Amorpho | Box Ghost | Bullet | Circus Gothica | Dark Danny | Desiree | Ember McLain | Evil Danny | Evil Syndicate | Freakshow | Fright Knight | Guys in White | Globulous Maximus | Johnny 13 | Kitty | King Gorge | Lunch Lady Ghost | Lydia | Nicolai Technus | Nocturne | Pariah Dark | Penelope Spectra | Prince Aragon | Skulker | The Mawgu | Undergrowth | Valerie Gray | Vlad Plasmius | Vortex | Walker | Youngblood