Short drabble, based on the idea who would have put the Christmas hat on the skull that we see in the picture Mark Gatiss tweeted.

Christmas Skull

"John, don't. I mean it." Sherlock made his way into the kitchen, waving away at something on his head.

"Oh come on, don't ruin the spirit. It's Christmas!"

"And I am not a Christmas tree. Wear it yourself if you like it so much," Sherlock huffed as he dropped down on a kitchen chair.

"I will," John replied as he put the Christmas hat on his head and tried to make the end of it stand up.

Sherlock rolled his eyes at him, while tapping the kitchen table with his fingers. "Bored," he murmured.

"What's that?"

"I'm bored. Nothing ever happens around Christmas."

"No family feuds that end up deadly? No Father Christmas who unexplainably falls through a chimney and dies?"

"Don't be ridiculous."

John frowned to himself. "I'm off to work."

"What?" The tapping immediately stopped.

"I needed to help out the emergency desk for a few hours. I told you that."

"No, you didn't."

"Yes, Sherlock. Yes, I did. Now play nice till I get back."

"You're wearing that?" Sherlock pointed disdainfully at the hat as John put his coat on.

"Why shouldn't I? Lots of people wear a Christmas hat around Christmas. You'd know that if you put aside your sulking for a bit and went out the door."

"Hm."

John waited for another response, but when it didn't come, he headed out the door, dumping the Christmas hat on the stairs.

It was the middle of the night when he got back to Baker Street. As he silently made his way up the stairs not to wake Mrs Hudson he could hear the soothing sound of Sherlock's violin. He wanted to wait behind the door before the piece was done, but then reminded himself of the last time he did that and Sherlock in the middle of a note stopped and yelled: "I know you're standing there, might as well come in".

He decided to enter through the kitchen door. Sherlock paid no attention to him and continued playing.

John poured himself a glass of water from the tap and made his way to his usual chair in the living room. He put the cushion with the Union Jack on the ground left of him and as he sat down his eye caught a red glow.

It was his Christmas hat. On top of Sherlock's skull.

After a moment of letting that scene sink in, John chuckled and pointed at the skull, only then realising that the music has stopped. He turned around to face Sherlock.

His flatmate was watching him with a large grin on his face.

"Thought I'd bring a little festive cheer to the flat," he said as he stood up and plugged in a cable. Bright lights filled the darkened living room.

He had even put up a fake Christmas tree. A small one, but still. An actual Christmas tree.

"I knew you were human after all," John said amused.

"Only sometimes," Sherlock said before putting the bow back to the violin.