This was another tumblr prompt from Halloween... so enjoy!
John found Sherlock in the labs of St. Barts the evening of Halloween. He'd been in search of the detective so he could drag him up to the hospital Halloween party. If he had to be there, he wasn't going to go and suffer alone.
Spotting him through the window, the blond pushed the door open and sighed, "Sherlock, just because it's Halloween doesn't mean you have to dress in all black. You should get creative with your costume. I'm sure you've got something hidden away in that massive head of yours."
Sherlock didn't even look up from his experiment to answer, "Really? And what will you be going as? Did you get a TESCO pumpkin costume on special? Maybe a set discounted vampire teeth and cape?"
John looked down at his crisp, clean uniform and blinked. He'd dragged it out of the back of the closet as a surprise for the younger man, but it seemed like it was all for naught now… he wasn't even paying attention. Frustration now clear on his face, "Yeah, maybe I'll run get the vampire set just so I can turn into a bat and fly away from this bloody place. Hell, maybe Molly could help me too."
Sherlock pulled his head away from the microscope to stare at John's figure before the older man's words fully processed in his head, "That was low, John, even for you."
As usual, no one noticed the Bride of Frankenstein enter the back of the lab carrying three cups of punch, "What about me?"
Both men looked up at Molly with childlike stares that read 'guilty' all over them and said, "Nothing," at the same time.