Pikachu is a yellow rat which controls electricity. I know this is needless to explain to all of you because Pikachu is too famous and too popular around the world.
By the way, all living creatures have DNA which contains information of the trait. Each of us has different DNA, which means that all of the human beings have different traits. This can apply to Pikachu as it is also a living creature even though it does not exist in the reality. Now I show some examples of different Pikachus.
This is the reality. All Pikachus do not always have exactly same appearance. Some of them are very very tall like a human. One of them is violent and too savage. Others are obviously just crazy. Like those Pikachu, there are lots of different characteristics. Don't feel pity for their appearance, because all of them have become distinguishable by having their own specific trait. You have a right to love them. But I won't love them. Who will love them? Nobody? Yeah, nobody. I know.