Chapter Summary: Colors are often associated with emotions, but saying someone looks a little blue is an entirely different thing than actually turning blue. Or, the one in which McKay becomes a living mood ring. Set in season one.

A/N: There is some real sketch science mumbo jumbo in here. But one sliver is legit because at one time in my life I did study marine bio. Yay for using my degree for something useful!

C is for Colorful

"Don't make him angry. You won't like him when he's angry."

Rodney did his best to ignore the snickers of laughter, knowing if he let them rile him up, he would only prove their point. Instead, he imagined he was back in his apartment on Earth, a technique he'd been trying out to keep himself calm. He had liked that place. It hadn't been very big, but had been cozy, and most importantly, peaceful. No life-sucking aliens threatening his existence. No annoying people to bother him while he worked. He wasn't usually nostalgic for much back on Earth, but that place… He missed it sometimes.

"I think he's a little blue, actually," Sheppard pointed out, as if Rodney couldn't overhear the conversation.

Rodney glanced at the backs of his hands on his keyboard. Dammit. He'd let his emotions wander again. Focus, Rodney.

"Sorry, buddy," Ford said with false sincerity. "Are we making you sad?" He chuckled again.

Rodney spun to face the two men who had been standing around his lab trying to get a rise out of him for the last fifteen minutes. "Oh, ha ha, very funny. Make fun of McKay because he might be dying from yet another malfunctioning Ancient device." His skin flushed bright red.

Sheppard's smile only grew as he got the reaction he wanted. "Oh, lighten up, McKay. You're not dying."

"How do you know?" Rodney sputtered, the crimson of his face deepening as he went on. "Are you suddenly an expert on the weird side-effects from these things?"

Sheppard snorted and Ford nearly doubled over as Rodney's complexion took on a purple quality. "Beckett said it's harmless," he said dismissively.

"As far as he can tell," Rodney argued. "I would feel a hell of a lot better if people like you would leave me alone so I can figure out how this thing works." He turned back to his computer. "Don't you have anything better to do?"

"Better than seeing if we can make you every color of the rainbow?" Sheppard asked with a wry smile.

Rodney took a deep breath and counted to ten in his head, willing his hands to turn back to their normal shade of pink. As long as he didn't let his emotions get too strong, nothing weird happened. He just had to be more even-keeled. He went back to reading the mostly translated 'instruction manual' for the device in question, hoping to figure out how to fix his pigment problem.

"What do you suppose would turn him green?" Ford asked Sheppard, going back to talking about him like he wasn't there. "We haven't seen that yet."

"I dunno," Sheppard replied. "Envy?"

There was a pause and then Ford said, "Hey, McKay. Are you jealous I'm not currently a human mood ring?"

Rodney saw his hands darkening again, but before he could respond, Teyla entered the lab, preempting his impending tirade. "Ah, Rodney," she greeted with a smile. "I was looking for you. I was hoping you might join me for lunch." She eyed his purpling skin and then the two giggling officers, frowning slightly at them.

Teyla, unsurprisingly, had been the only one who had not thought Rodney's new chameleon-like abilities were hilarious. Or at least, if she did think it was funny, she had kept it to herself rather than teasing him like everyone else. He noticed that instead of making fun of his plight, she had made a point to check in on him a couple times a day. This came in especially handy around mealtimes, when he had to be around even more people who couldn't seem to stop laughing at him. He had never considered himself all that close with Teyla, but he appreciated her effort of friendship more than ever now.

And he could definitely use something to eat. He swore that whatever was making him change colors had supercharged his metabolism as well. "Lunch would be lovely," he said, standing and throwing a smug look at the other two, daring them to continue their taunts now that Teyla had shown up.

Sheppard and Ford made to follow them, but Teyla stopped them. "You may join us only if you do not antagonize Rodney."

"We weren't antagonizing—" Sheppard started before Teyla cut him off with a raised eyebrow. "Fine. I promise we'll be civil."

Rodney's skin took on a slightly orange tone, and he hurried to move out of the room before anyone noticed.

"For the record," Sheppard said as they walked down the hall, "we were trying to help. We were figuring out what color goes with each mood. For science, you know?"

"Oh, so helpful," Rodney quipped, focusing on the thought of food and hoping that he could keep it together long enough to get through lunch without doing an impression of any of the characters in Willy Wonka and the Chocolate Factory.

A week later, the jokes had worn into real concern as Rodney still hadn't managed to crack the secret to reversing the device's effects. Not only was he still displaying every emotion in a colorful array for all to see, but it now also seemed the colors were becoming stronger and more permanent. In fact, in the last few days, John didn't think he'd seen McKay's natural skin tone at all.

Carson still claimed that physically, the transformation was mostly harmless (Rodney hadn't much liked the use of the word "mostly" here), but John could tell it was wearing on the scientist. It reminded him of some of the pranks he'd pulled back in school. Funny when his roommate woke up with a Sharpie mustache or inappropriate word written across his forehead—less funny when it was still there a couple days later and the guy was in his sister's wedding party.

Practically speaking, they'd had to push all of their non-critical missions back until the problem was resolved. They couldn't very well take a color-changing astrophysicist along when they were trying to meet potential trading partners, and it would just be kicking Rodney when he was down if they went without him. The problem was, the longer they were stuck in the city, the fewer excuses John had to put off doing all the mundane office tasks he usually avoided by packing his schedule with off-world visits.

So, motivated by desperation to get out of writing up the SOP for storing the foodstuffs they procured from their trading partners (which he'd really been hoping to pawn off on one of the lieutenants), and, of course, his concern for McKay's well-being, John marched into the science lab, determined to speed up the process of figuring out a solution so things could get back to normal.

He found the subject of interest hunched over his computer, his skin flushed a deep red which indicated he was probably stuck in the same spot he had been for the last three days.

"Any progress?" John asked anyway.

"Of course not!" Rodney snapped, waving a frustrated hand toward the computer screen. "This is complete nonsense. Whoever programmed this device was an idiot."

John leaned in to look over Rodney's shoulder at what seemed to be a long string of Ancient letters. "What does it say?"

"It's a base code, how the Ancients recorded DNA sequences." Rodney smacked a few keys and the screen changed to more Ancient mumbo-jumbo. "Basically, I've figured out the device changes the expression of certain genes, rearranging how the RNA interprets the alleles to make proteins, which are affected by the hormones released any time I have an emotional reaction."

"Huh," John grunted, squinting at the screen as if that would magically make him understand the alien text. "It's rewriting your DNA?" That didn't sound harmless to him.

Rodney shook his head. "Not rewriting, just activating what are normally dormant genes and suppressing others. So now, instead of making melanophores like my body should be, it's making chromatophores."

John frowned, trying to remember his high school biology class. He remembered something about Punnett squares and figuring out whether Sally and Fred's baby would have a widow's peak, but that was about as far as his knowledge in genetics went. "Chromatophores?"

"They are the cells cephalopods have that allow them to change color," Doctor Zelenka supplied from his desk a few feet away. Glancing up from whatever he was working on and seeing John's still confused expression, he added, "Octopus and cuttlefish."

"Ah." Yes, John had seen a National Geographic show about that once. "But how does that even work? I mean, an octopus is pretty different from a human."

"You'd be surprised how much DNA we share with them," Rodney grumbled. "We're all a few base codes away from being an onion. Switch around a few G's and T's and suddenly you've mutated yourself into an entirely new species." He motioned at the screen dramatically. "This is exactly why biology is closer to voodoo than real science."

"So, can you make the device switch your DNA back to making the melo-whatever instead?"

Rodney sighed. "That's the trouble. I can't figure out which alleles to activate. If I do the wrong ones, I could have bigger problems than being a human mood ring."

"You should ask Doctor Ishihara," Zelenka sang.

Rodney took on a crimson hue. "I don't need Ishihara. I can figure it out myself."

"Wait, yeah," John said, snapping his fingers and pointing at Zelenka. "He's the head of the biology department, right?"

"Not only that, but he specializes in the genetics of marine invertebrates." Zelenka stopped pretending to work and leaned forward over his desk on his elbows, smiling smugly. "I believe he mostly studies copepods, but still. His knowledge would come in very handy, I would think."

"I don't need Ishihara's help," Rodney repeated firmly.

"Why not?" John asked.

"Yes, Rodney. Why not?" Zelenka raised his eyebrows, inviting the answer he clearly already knew.

Rodney's skin shifted toward an orange tone. "Ishihara and I don't exactly see eye-to-eye," he said. "I doubt he would help me."

"Rodney," John drawled. Of course McKay had pissed off the person who could solve his problem.

"I may have insinuated some things about his education, okay?" Rodney admitted with a grumble. "And, anyway, I really don't need his help. Compared to theoretical physics, genetics is child's play. I can figure it out on my own."

"Yes, but how long will that take?" Zelenka interrupted, waving a hand at him. "And in the meantime, you continue to give me a headache with your constant color changing."

"Yeah, well, no one asked you, did they?" Rodney turned from his computer to face his counterpart, narrowing his eyes. "What are you even doing here?"

"I work here," Zelenka answered defensively. "This is my lab, too."

"Well, then work!"

Zelenka mumbled something that didn't need to be in English to be understood, but bent back over his computer.

John ignored their bickering, moving toward the door. "McKay, come with me."

"Where are we going?" Rodney asked, but made no move to get up.

"To apologize to Ishihara for whatever stupid stuff you said to him and ask for his help."

"What?" Rodney's eyes went wide at the same time he began turning yellow. "No, I—"

"Rodney." John swiveled around and pinned him with a stern glare. "Do you want to be a cuttlefish forever or do you want to figure this out?"

The scientist considered for a moment, his skin flashing through an array of colors.

"Well?" John prompted impatiently.

"Fine," Rodney growled, finally settling back to a red-orange color as he slid out of his chair. "But just so we're clear, I don't need his help."

"You know, we never did find out what turned you green," Lieutenant Ford said exactly one week later.

They were walking back to the gate after an incredibly long and boring meeting with the Bellinians, which had been just fine by Rodney. Just because he'd been cleared for off world travel again didn't mean he wanted another adventure so soon.

"Hey, yeah," Sheppard chirped in, just realizing this himself. "We saw every other color, but never green." He turned around from his position at the front of the group, walking backwards up the dirt path. "So what was it, McKay?"

Rodney rolled his eyes, wondering if he was ever going to stop hearing about his week as a human mood ring. "I don't know, okay? Can we move on to something else?" He motioned toward Ford. "Like, hey, did you get a haircut?"

Ford gave him a cheeky grin. "No, come on, McKay. Tell us. What emotion turned you green?"

"Perhaps we could assume it is an emotion that Rodney does not often display," Teyla suggested with a small smile. Great, she was turning on him now, too?

"Hmm." Sheppard frowned thoughtfully, but his eyes were sparkling with laughter. "What emotion does McKay never feel?"

Rodney sighed, bemoaning the fact that he was being made fun of yet again on an otherwise very pleasant, uneventful mission. He'd just been thinking how good it felt for things to be back to normal. Well, he supposed his team making fun of him was pretty on par for the course, but it would be nice if it was about something other than the color changing. He'd already endured enough of that, between the actual ordeal and the fact that he'd had to schmooze Doctor Ishihara into helping him fix it (a deal which included sharing the very limited supply of good coffee with the biology department).

"Empathy?" Ford guessed. "Kindness? Compassion?"

"I was thinking more along the lines of humility." Sheppard added with a smirk.

"Oh, hardy-har-har," Rodney said, making a face at them. "Maybe it was feeling appreciated or respected, since I never seem to get that from you people."

Sheppard held a hand to his chest as if he was wounded by the comment. "Ouch. Feeling a little red, are we?" He chuckled at his joke, spinning back around to walk the right way.

"I am curious," Teyla said sincerely. "Did you ever turn green?"

Rodney hadn't been paying all that much attention to which color he'd been turning, and had been much more occupied trying not to turn any color for most of the ten days he had been under the effects of the device. But because Sheppard and Ford had been so obsessed with trying to get him to turn green, he had noticed when it happened. And in the ten days, it had only happened once. At least, strongly enough that he'd undeniably been green, because a lot of times when the emotions were weaker, the colors muddled with each other and were harder to identify.

It had happened after a long day of trying to figure out the device, about four days in, and he'd reached a level of frustration where he was sure he was going to be stuck broadcasting every emotion in technicolor for the rest of his life. Sheppard and Ford had still been teasing him relentlessly at that point, as had most everyone else in Atlantis, and he'd been on the verge of a breakdown.

After a late dinner (so as to avoid the crowd), he'd gone for a walk to a lesser-trafficked part of the city and ended up out on a balcony looking up at the stars. It wasn't something he did very often—he was much more likely to stare at a screen into the wee hours of the morning—but whenever he did take a moment to look up, he wondered why he didn't do it more often.

Even with the lights from the city at his back, the night sky on Lantea was impressive. Much different than Earth, of course. The constellations were all different, for one. The Ancients didn't really have a need for constellations, though they'd charted a few patterns of stars in the night sky. Rodney preferred the ones he'd made up based on the more prominent stars, like the "big whale" one and the "smiley face" one.

There was something akin to the Milky Way, but it was different, too, in a way that was hard to describe. It looked similar, a thick band of stars speckled like dust across the sky, but it felt alien. Maybe just because he knew that somewhere up there, one of those dots was the Milky Way galaxy. Still, it was beautiful to look at.

That evening, as Rodney had stood alone on the balcony, gazing at the stars and breathing in the salty air that had somehow become so associated as home in his mind these last six months, he had finally allowed himself to relax. Had enjoyed the peaceful sounds of the tide lapping up against the glittering piers below him. Had thought about how, despite all the dangerous missions and outrageous situations that happened to him almost daily, he really, truly loved it here.

He hadn't noticed the color of his skin out under the starlight, but when he'd walked back into the light of the city a while later, refreshed from his time reflecting outside, that's when he'd noticed that he had gone green. Bright, Kermit-the-Frog, unequivocally green. It was the only time he had so obviously turned that shade, and that was exactly why he didn't want to share with them now.

Because how pathetic would he seem if they realized that green meant he was happy, and that they'd never seen it because he never was?

The thing was, that wasn't even true. He was happy in Atlantis, just as he'd been contemplating on the balcony. He did meaningful work here, had saved the galaxy more than once, and really, what more could he ask for? He had more friends now than he'd had in a long time—maybe ever. And yet, he realized with more than a little embarrassment, that he was always so busy being irritated at someone, or terrified of something, that he didn't leave much time to appreciate his life.

Then again, it wasn't like pessimism was a switch he could just flip and suddenly turn into Susie Sunshine. He couldn't help but notice all the terrible things that could happen, and that's arguably what made him so good at his job.

But maybe he would try a little harder to be more grateful for the good things. To remember to enjoy his life a little more.

"Rodney?"

He glanced over at Teyla, who was still awaiting a response to her question.

"Oh, umm…" He shook himself out of his thoughts, deciding how to answer. "No. I never turned green. Guess we'll never know what it was. That is, unless Sheppard wants to give the machine a go. Of course, he would probably just be yellow the whole time."

Sheppard glanced back at him. "What's yellow again?"

"I think he was yellow when he was scared," Ford supplied.

"Ah, not only fear," Rodney corrected, raising a finger. "It was for confusion, too. And Sheppard definitely spends ninety percent of his time being confused."

"I think what you mean is that I spend ninety percent of my time being awesome."

"And the other ten percent?" Teyla asked.

"Obviously the other ten percent of the time I'm being hilarious," Sheppard answered easily.

"Obviously." Rodney smiled to himself, satisfied that his diversion had worked as his teammates forgot about pestering him and instead discussed which colors each of them would display under the influence of the device. Which was funny, because if he had been a color at that moment, it would have been green.

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