A/N: I do not own No. 6 or Fruits Basket. This is just a random idea a friend and I had.
Kyo stormed into the room that Yuki was in, slamming the door behind him. "HEY, RAT!" Kyo yelled, determined to finally win a fight against his archenemy. Much to his surprise, not only did Yuki react, but a boy he had never seen before did as well. "WHAT?" both shouted back.
Confused, Kyo said, "Um... I was talking to Yuki. Who are you?"
"Rat." replied the stranger.
"Ohhh. So when I said rat... Okay. I get it now." Kyo muttered.
Rat blinked. "Why did you yell 'rat' if you were speaking to Yuki?"
"'Cause he's the rat, of course." Kyo retorted.
Rat glanced at Yuki in confusion. "What is he talking about?"
Yuki sighed. "I'm the rat from the Chinese Zodiac-"
Kyo interrupted, "What are you doing? You can't tell him!"
Yuki rolled his eyes, "You all but told him yourself!"
At this point, Rat was beginning to think both of them were insane. This only increased when, after a few more minutes of arguing (which mostly consisted of "Did not" and "Did too" repeated several times after the point where it got annoying), Yuki pulled out a leek and proceeded to chase Kyo around the room, brandishing it like a sword.
Just when Rat was considering leaving while the duo were distracted, a girl walked into the room, and Kyo and Yuki ran into her. Five seconds later, an extremely confused Rat asked the girl if they had really just turned into a cat and a rat.