Chiyo-chichi (Chiyo-Dad, or "Father Cat" in the dub) is a strange creature that appears in Osaka and Sakaki's dreams. He says he's not a real cat before he tells Sakaki to "find a real cat."
What kind of creature is he? Where did the author get the idea of creating him?
He's the strange creature in the middle -- he doesn't like tomatoes because they are red :