Caitlyn is a main villainess in A Cinderella Story: When in Phuket and is also one of Shelby Cummings's posses, alongside Madison. Caitlyn is a beautiful brunette haired Caucasian teenage girl who were turned into a passerine bird called white-rumped shama as a punishment for abusing her power. During her youth, several boys were attracted to her, but she would constantly abuse her powers and bully others for her sadistic amusement. Fauntleroy Donaldson briefly had a crush on her for a long time due to how beautiful she looked. The Dark Magic Authorities soon caught onto her and soon humiliating her by turning into a female white-rumped shama. They decided to give her a slow and painful transformation, starting from feet turning to talons then nose turning into beak then arms becoming wings then a full white-rumped shama. He then decided to look after Caitlyn until they found the Emerald Gemstone of Dreams, which they could use to turn her back into her former ravishing self. Fauntleroy was the only one who saw this and was saddened.
Caitlyn realizes that the Spellmans are magic practitioners and hopes they can get her one step closer to becoming a full human girl. As she was a magic practitioner , she knew what magic practitioners were like and could do. They ignore her, and she is extremely annoyed at Sabrina's mother Diana Spellman as she forced them to hurry away and not listen to her story. Caitlyn manages to steal the emerald gemstone and finally turn herself into her human form. She loves her new body and uses a small spell to temporarily stun Diana in the process.
Then she was seen entering a resort, where she is in a light blue Porsche and is wearing a pretty cobalt blue dress. Diana, who is also there, is stunned by her beauty- but soon realizes she has the emerald gemstone on her neck, and she follows her. In the resort, Caitlyn admits to Fauntleroy that she was only using him all along. Fauntleroy is extremely saddened and upset, as he wanted to be with her. Fauntleroy hugs her one last goodbye hug and moves on. But then Diana appears and calls her out for being the bird. Caitlyn acts innocent and totally human until she spits out bird feathers. Diana mocks her and says she needs the emerald gemstone. Caitlyn tries to flee, she would never give this woman the stone - what if she turned her back into her feathery state, knowing she was the bird? Diana rushes in front of her and tells Caitlyn her story. Caitlyn is not put off and is infuriated. She pushes Diana against the wall with one of her dark magic spells and gives her a lecture. 'I just got my life back, that's all' she says. Diana still wants the emerald gemstone. Caitlyn laughs sinisterly and is about to use a spell to turn Diana into a white-rumped shama when Fauntleroy appears with the emerald gemstone in his hand. Caitlyn is stunned, how could he get the damn emerald gemstone? He won't turn me into a white-rumped shama anyway, he loves me so much. That's what Caitlyn thinks. But Fauntleroy says "First trick of my new act, it's a doozy". This reminded her of her last and final transformation, and she panics. She coughs feathers. She hopes this is not what she thinks it is and smiles at Diana. Then feathers appear everywhere and she sinks. She then stares at her feet, which were no longer shoes, they were white-rumped shama feet! She begs Fauntleroy to not continue and she continues to stare at Diana, who is completely shocked in horror. She sees feathers appearing on her arm, then she coughs feathers once again. Fauntleroy smiles at her. Caitlyn realizes she has a small beak. She tries to stop the curse and beg Fauntleroy to let her go, but she can't as she can only make a "tck" sound. She becomes shorter and gives one final stare at Diana, who smiles at her. She tries to do something, but is unable to and falls under her pretty cobalt blue dress and becomes a white-rumped shama yet again. Fauntleroy is happy that he has a passerine bird in his birdcage in order to do his magic tricks with. Caitlyn was once a lady of extreme beauty, now she is a passerine bird.