I would like to formally point out I wrote this before season 3 came out and just re-discovered it.
So, I just got the most wonderful mental image of John singing 'Hey Dragon' to Sherlock.
Season 3 Plot twist: Sherlock was dragon the whole time after his death.
John gets sent on a mission to defeat the dragon guarding 221b Baker Street.
John realizes the Dragon is Sherlock and starts to wonder why he left the Shire.
Hey Dragon
John was lying down on his crappy small bed, eyes watching the ceiling with no interest. He had been a total bummer ever since Sherlock committed his suicide, moving out of Baker street and into some crappy-ass apartment, unable to handle the memories. When his phone went off, he let it ring a few times before answering with the monotone "Hello?" That usually ran his life nowadays.
"John? John Watson?" The voice of Greg Lestrade rang through the other side.
"Yes, this is me." John was dully surprised. Nobody had tried to contact him in weeks, all saying he was a lost cause.
"Well, pack your shit; I got a job for you." This actually got John interested. He thought all the people at Scotland Yard hated him because he was so close to Sherlock.
"What job?"
"Er, well, you remember your old place right? Baker Street with… him?"
Of course John remembered. John remembered every little thing. The way he would pop his collar and do that little smirk that made him look like an utter ponce. Or the way he used to store eyeballs and livers in their shared fridge and bossed poor old Miss Hudson around. Or when his brother would come over and insult John's complete life, which they both knew every second of…
Wow. John really needed to move on.
But certain matters came first.
"What happened?" He asked. Miss Hudson had refused to sell the apartment, so all of Sherlock's (And, to be honest, most of his) things were still there.
"Well… you may want to come see."
"Are you fucking kidding me, Sherlock?"
A giant golden eye peered into the young hobbits face. "Help John, I don't like being a dragon."
And with that, John Bilbo Baggins Arthur Dent Watson turned and hailed a cab.
"Why did I ever leave the shire?" John asked himself as the car sped away from Sherlock's screams of dragon rage.
Fin.