Tracy Stewart is a high school student and a chimera hybrid. She is an antagonist in the horror MTV series Teen Wolf and is a member of Theo's chimera pack, serving as his right-hand.
Tracy Stewart was a senior at Beacon Hills High School in Season 5. She talks to Ms. Martin, who is acting as the school guidance counselor. Tracy explains that she's been having night terrors and relays one in particular that has to do with a raven knocking at her skylight. In reality her skylight doesn't even open, but in the dream it suddenly opened during a thunderstorm and she got up to close it, balancing on a chair. She saw someone pull the chair out from under her, and in the morning her father found her on the floor.
Ms. Martin tries to convince Tracy that it's just normal nerves, but Tracy vomits black ooze all over her desk, along with a raven feather.
Tracy starts having hallucinations while at school, and Lydia convinces her mother to let her take Tracy home. It turns out that Tracy is also sleepwalking, and she delivers herself to the Dread Doctors, who have been injecting her with something. She appears to be turning into a hybrid werewolf and kanima. In Dreamcatchers, she begins to ooze paralytic kanima venom and while in the Animal Clinic, develops a tail.
She kills her father and wounds two police officers that are transporting Donovan, then hunts down the other people who have tried to help her, including her therapist and Mrs. Martin. She kills the therapist and tracks Mrs. Martin to the school. Scott, Liam, Stiles, Malia, Lydia, and Kira approach her at the school. Tracy grabs Hayden's arm, cutting into her, although the wounds don't stay. She then passes out and leaks silver fluid. They take her to the Animal Clinic for diagnosis.
While there, Tracy comes to and attacks everyone, leaving them paralyzed. She then tracks Mrs. Martin to the Sheriff Station. Lydia and Kira arrive at the station at the same time, since Lydia realized what Tracy's killing pattern was. Kira takes on Tracy cuts off her tail, but not before Tracy slashes Lydia in the side.
Malia recovers from Tracy's venom before Scott and tracks her to the Sheriff Station. She finds Tracy downstairs with Mrs. Martin. Malia is able to take her in the ensuing fight, where Tracy finally wakes up from her night terror. Just as she does, the Dread Doctors show up and inject her with more silver fluid. They declare her a terminal case and leave her to die.
Jordan Parrish steals her body and burns it on The Nemeton.
Afterwards, Theo Raeken resurrects her and now she is part of Theo Raeken's pack.
Sometime in the not so distant future, she is breaking into Eichen House with Theo, Josh and Corey, she kills at least one guard and roughs up Valack. They plan to retrieve Lydia Martin, so that they can use her to lure Parrish to them.
She and Theo go to Beacon Hills Memorial Hospital to finish what she started. The driver of the prison transport vehicle is still alive and he could ID Tracy as the killer, so she kills him by injecting venom into his IV bag thus killing him instantly, she knew how to do this because her father one defended a guy on death row and this allowed her to learn how lethal injection works. In the tunnels, after paralyzing Stiles, she and Josh attack Scott but they fail.
She and Theo arrive at the school, they're tracking The Beast, they enter the school and she asks Theo if its true it killed over one hundred people, Theo tells her that is was closer to five hundred. Then they see that the Dread Doctors have left another message for it, Tracy is confused because she believed the beast just to be another kid turned Chimera Theo tells her that the doctors don't care about the kid underneath, they just want the beast. One of the doctors appear right before them and she attacks but her hits have no affects and she is knocked into a locker then the beast comes from around the corner and Tracy is terrified, it roars so loud that she's forced to close her ears and by the time she looks up, the doctors and La Bete are gone.
Tracy, Corey and Josh capture Deucalion. She tells Theo that Deucalion knows why he's there.
Tracy kills a guards and enters Eichen House along with Theo Raeken and the rest of his pack. Given a signal from Theo, she grabs Valack and pins him to the wall, the prepare to take Lydia but Parrish in Hellhound mode shows up.
Tracy is instructed by Theo to attack Hellhound Parrish and she does by her venom appears to have no effect on him, she is then knocked into the wall by the powerhouse hellhound. She scratches one of the guards, it is unknown if he's dead or just paralyzed but she then takes his radios. Some time later she makes it outside Eichen House, Tracy scratches Parrish in the back and she grabs Martin. Scott attempts to reason with her but it doesn't work, so Natalie Martin shocks Tracy with taser stick.
Tracy tells Josh that he has to be the one to put the mask on because his powers will prevent him from dying. As Deucalion becomes to much to listen to, Theo tells her to paralyze him but Deuc first asks her how weak was she before becoming a chimera? Deucalion explains to her that its the truly powerless that are so eager to display newly found power. Later she shows up at the McCall House to break the mountain ash barrier which allows The Desert Wolf to enter.
Tracy helps a wounded Theo back to the lair, she lays him against the wall seeing as he can't stand on his own. They begin to kiss but Theo is in pain, so she wants to stop and take a couple of more days to think of a new plan but Theo is against this. She tells him that she's not like the other because she's can't take his pain, Theo tells her that she can do something else for him, he then takes her powers. She tries to fight back and begs Theo to stop but he doesn't. This eventually leads to Theo killing her.