One common theme is self - discovery. When a girl turns into a cat, she often has to learn new things about herself and her abilities. For example, she might discover new senses or ways of interacting with the world.
Well, it might be due to a powerful magical artifact. She could have accidentally touched or used an enchanted item that had the power to turn humans into animals, like a cursed amulet. Or, in a more spiritual sense, it could be a connection to a spirit world where cats are guardians and she has been chosen to take on that form for a special mission. There could also be a deal made with a supernatural entity that she has to fulfill, and the transformation is part of the deal.
Another reason might be related to some kind of spiritual or mythical connection. In certain mythologies, there are beings that can transform between human and animal forms. She could be related to such a being, and due to some trigger, like reaching a certain age or entering a specific place, she turns into a cat.
She probably has to adapt to moving around on four legs instead of two. Her perspective of the world also changes. Things that were easy to reach as a human are now out of reach or difficult to access.
There's also 'Cat President'. In this visual novel, there are elements where a girl might have some cat - like transformations. It has a unique and humorous plot that involves various characters and their relationships.
It can also be used to explore different aspects of the characters. The girl in cat form might have different behaviors and instincts that play into the relationship. Maybe she's more playful or shy as a cat, and this affects how the romance develops. The transformation can also create some comical situations, like when she accidentally knocks things over in cat form, which can be a source of bonding between the characters.
There's also 'Kemono Friends: Pavilion'. It involves a unique world where the girl - animal transformation is a key part of the story, and there are romantic undertones as the characters interact and build relationships. It has beautiful visuals and an interesting plot.
One idea could be that Batman is turned into a cat by a villain's new experimental device. As a cat, he has to rely on his natural feline abilities like stealth and agility to still protect Gotham. For example, he could use his cat form to get into small spaces in buildings to gather evidence or spy on criminals.
Well, it could be about a woman who, perhaps due to a magic spell or some kind of supernatural occurrence, transforms into a cat. Maybe she's a witch who accidentally casts a wrong spell on herself, or it could be part of a curse. There are many possible interpretations depending on the context of the story.