Once in Panem, Katniss Everdeen encountered a weird looking species she would call a "muttation". It had a horse's body but had one horn sticking out at the middle of its forehead. And after a minute of staring at the mutt, a rainbow was released in the blue sky and the muttation vanished. As she hurried home, she was going through her history books, and found a picture of the mutt she encountered with. It was called, "Unicorn."