A/N: This story is partially the inspiration of a conversation with AOB in which I was challenged to write a fic involving a sock and a baby alligator. This morning a bit of light reading about quantum physics, bosons, supersymmetry, fermions, oscillation frequencies, gravitons, worldsheets, closed and open strings, compactification, dualities, eternal inflation, Theory of Everything, lower-vacuum bubbles and extra dimensions... well, you'll see...

Disclaimer: Don't own anything. Pure silliness with a whiff of quantum physics. Read at your own risk.

Where's my other sock? John let out an exasperated sigh. "Sherlock, have you seen my sock, the one with the green and red stripes?"

Silence.

"Sherlock!"

Silence.

"Sherlock, that was not a rhetorical question. Sock. Have you seen my other Christmas sock?"

"No, John. Why would I remember the locality of your festive outerwear for your appendages? Boring." Sherlock languidly answered from the direction of the living room.

Several minutes passed wherein the blond doctor exhausted all his powers of deduction without success as to discovering the location of his missing sock. During this time a long series of distinctly non-French words punctuated the shuffling and banging of drawers and papers.

"I can't find it anywhere?"

"At the risk of offering a rather supercilious suggestion, why not wear a different pair?"

"Because I don't have another pair of Christmas stockings, that's why! I need them for the Christmas party."

"Clearly your definition and my definition of "need" are different. I sincerely doubt you will lose your lower phalanges due to frostbite or be killed by an angry mob of party attendees if you fail to wear the proper foot decoration."

"Oh, just shut up. You are not helping the matter."

"Which was my initial response to this escapade in the first place…." Sherlock muttered under his breath.

John gave the detective a glare icy enough to freeze the pointy ears of an elf then flopped back into his chair in a defeated slump. He stared moodily into the dancing flames of the fire flickering in the hearth.

A tense silence ensued.

John sighed loudly.

Sherlock shifted in his position on the sofa and flipped a page on his magazine.

More silence. John remained rooted and morose while the holiday cheer melted from the atmosphere.

"Once you have eliminated the impossible, whatever remains must … "

"…must be the answer." I know that, Mr Genius, John snapped back. "The problem is that there is no hiding place that remains. I've eliminated all possibilities. My sock has vanished. Pure and simple. Just disappeared completely from this flat."

"Ah, but there you are wrong, John," countered Sherlock. "I have it on the good authority of Hawking, Witten, and Maldacena that you have not searched every possibility."

"You're wrong. I've looked everywhere, bedroom, living room, desk, fridge, kettle, coat pockets, violin case, even my sock drawer."

"Have you checked the other seven dimensions?"

"Huh? What are you talking about? Of course, I've not checked alternate dimensions. I'm looking for a lost sock, not a mathematical equation."

"So, you haven't looked everywhere then." Sherlock's eyes fluttered open for a few seconds as he glanced over at his flatmate.

John just shook his head.

After several minutes, Sherlock spoke up. "The problem of the missing sock has troubled physicists and mathematicians alike for years. In order to explain this universal phenomena they have developed the String Theory, which has now evolved into the M-Theory – short for "The Mother load Theory' - in case you were wondering what the 'M' stood for," he added.

"Sherlock, now is not the time for one of your jokes," John grumbled.

Ignoring the protests, Sherlock continued. "According to the M-Theory, there are 11 dimensions (10+1 whereby the one equals time). Now obviously, humans operate in a 3+1 dimensional landscape; so, in order to explain this one must compactify."

John glanced over at his friend to see if he was really serious. He was.

"There are a couple ways in which one may compactify the dimensions. I favour the second. Simply put, we are stuck in a 4 dimensional subspace of the full universe. An analogy would be that our world is the crack in a crystal vase that equals the full cosmos. Of course, gravity is not confined within our 4-dimensional crack. Gravity seeps through all dimensions, even those invisible us. We only perceive the existence of these dimensions, therefore, by the unexpected phenomena that occur from gravitational forces acting in alternate dimensions."

John stared, mouth gaping like a sunburned trout at the lean figure who'd not so long ago claimed astronomy was useless and didn't care whether the earth rotated round the sun or a teddy bear.

"So you see, John, it's really quite simple. As I mentioned before, once you've eliminated the impossible, whatever remains must be the solution. Your Christmas sock has just been a victim of a gravitational pull into another dimension." He raised his dark curls from the sofa's cushion and tossed a triumphant look in the direction of John.

John blinked and closed his mouth. He opened it again as if to speak then closed it again. He shook his head slowly. "Amazing, fantastic, incredible, remarkable, extraordinary, astounding, and astonishing…"

Sherlock glowed.

"I simply can't understand how such information is pertinent to your work and worthy of your brain-attic," he continued. "How can you imagine quantum field and gravity theories are useful to locating my sock?!"

The younger man's face fell. "Whatever do you mean, John? Of course, they're relevant. I've just explained to you where your Christmas sock is. What more could you want?"

"The actual sock."

"Oh, well, I can't help you with that. Quantum physics doesn't allow one to predict when, precisely, the gravitational forces on your sock may change and sling it back into one of our visible dimensions."

"I suspected as much." In spite of himself, a small smile played on his face as he resigned himself to wearing non-festive, but matching, socks to the Christmas social.

Just then a glint of green and red knitted cloth caught John's eye. "Sherlock, what have you done?! My sock!"

"John, do calm down. It's perfectly normal for particles of matter to cross from one dimension to another."

"No, it's not that. It's my sock. It's on your alligator!"

"Technically, an American crocodile," Sherlock replied docilely. "What about him? I'm using him for one of my experiments." Sherlock flipped another page. "Oh don't worry, I need him alive for my experiment. He goes back to the zoo once I'm finished."

John waved his hand. "No, no, that's not what I meant. I meant your crocodile is wearing my Christmas sock! You've even cut little holes in it for his legs and head."

"Your powers of observation exceed the norm today."

"You've made an alligator sweater out of my Christmas sock!" John repeated slowly.

"Crocodile," Sherlock corrected.

"Crocodile sweater…" John's voice trailed off. "But he's an amniote."

"Very good, John. An A+ in biology for you today," the detective settled himself deeper in the cushions on the sofa.

"He's a bloody amniote, a reptile. He doesn't need a sweater. He's an ectotherm, Sherlock." John stared at the green, leather-skinned tetrapod lying on its rock with a brightly woven green and red sock-sweater decorating its body. John still swears the beast winked back at him.

"John, haven't we already been over this before," Sherlock drawled from across the room. "Our definitions of 'need' are different. The crocodile needed a sweater; you need to get going or you'll be late for the Christmas party."

John fell silent. What could he say? He turned and changed into plain black socks and headed out the door.

"See you later," he called as he closed the door behind him.

"Don't get lost in another dimension," Sherlock muttered. A brief smirk crossed his face as he glanced over at the festive amphibian. "And a happy Christmas to you too, my meretricious friend."

A/N: I warned you! Feeling like a science geek yet?