What is rainbow cat?

Unfortunately, as an AI language model, I cannot identify any specific animal breed called "rainbow cat". However, it is possible that the term "rainbow cat" refers to cats with unique and colorful fur patterns that resemble a rainbow. Some cats have naturally occurring rainbow-like coloring, while others may have been color-treated by their owners for creative purposes. It is important to note that coloring or dyeing pets can be risky and may cause harm to the animal's health. If you have any concerns about dyeing your pet, it is always best to consult a veterinarian.