Dogs and cats used to be animals before, but when Japan developed further, one scientist invented a type of medicine to test on animals. Scientists have taken a red potion and poured it into dog and cat food. When they ate it, there was no reaction or anything, but after 3 days. Scientists were shocked and stunned to find that dogs and cats did have the same appearance as humans but still had animal ears and tails. Therefore, this red medicine was named "AG" An abbreviation for animal girl.