I don't own Naruto.
"Naruto, your element is wind. Now, wind is strong against lightning, but weak against fire. When used against fire it usually powers up the fire jutsu rather than nullifying-canceling-it. But when used against lightning the lightning jutsu will either weaken or die."
"So this is a good element."
"That's right. Now that Sasuke is a missing nin, your wind nature will help you defend or defeat the Chidori."
"Ne, ne Kakashi-sensei, does that mean that I can make flames stronger if I use it with another person?"
"Of course."
"YOSH! Lee! Gai-sensei! I CAN FAN OUR FLAMES OF YOUTH!" Naruto yells and POOF!s into a green jumpsuit, to Kakashi's horror.
"NARUTO-KUN! We knew you could do it!"
Commence sunset jutsu. And double tackle-hug.
"NOOOOOOOO! I'VE CREATED A MONSTER!" Kakashi cries in distress.
XXXXXXXXXX
Later at the memorial stone...
"I'm so sorry sensei, I should've known that was coming. He's the number one unpredictable knuckleheaded ninja after all. Is that why you never wore green though? It looks good on blondes."
Kakashi then also POOF!s into a green jumpsuit. "If you can't beat 'em, join 'em, right?"
"YOSH! MY ETERNAL RIVAL HAS FINALLY EMBRACED THE POWER OF YOUTH!"
"GAI-SENSEI! KAKASHI-SENSEI!"
And so begins the horror of the 4 green beasts of Konoha, and the fall of one of the most stoic nin ever. On the bright side Kakashi was never late anywhere ever again, and people saw that green really went with silver and red. Kakashi is now known as the christmas beast of konoha. The note on his bingo book says, you'll hear him, you'll see him, you'll laugh at him, but as soon as he reaches you the last thing you'll see is a christmas tree with a red ornament, and a silver bell on top.
The ninja world would never be the same again. They started a trend, if Kakashi, who'd been avoiding youth for almost all of his life could fall to the power of youth and embrace it, then there was no use fighting against it.