It first happened when he was thirteen.

Spock was running from Stonn and his acquaintances. They'd threatened to escalate their bullying to "physical stimuli," so the only logical conclusion was to flee. He believed they would not pursue him beyond the educational facilities, but that hypothesis had proven incorrect. His situation was rapidly deteriorating. By his estimation, they would catch up with him in about thirty seconds. He would have to find a place to hide. He glanced around, but the only possibility was to climb the tree near him and land on the roof of a nearby dwelling. However, the branch he needed to leverage himself upwards with was just out of reach. He heard the steady thud of his pursuer's feet. Twenty seconds. Ten seconds. Five…

Spock gathered himself, and leaped with all his might. His body twisted and sprang in a strange, unfamiliar way. He reached desperately above his head, and dug into the branch with his nails. Strangely, they held him with enough strength that he was able to swing the rest of the way up. He got a flash of black paws beneath him as he scurried to the roof, then they transformed back into hands. He stared at them as Stonn and company ran by on the street below, calling for him, apparently unaware of his current whereabouts. When he was sure they had traveled a safe distance, he crawled back onto the branch, examining it. Deep claw marks that could not have possibly been left by his fingernails assured him that the black paws had not been merely a hallucination induced by momentary fear.

What were they, then?

Spock immediately concluded he could not go to anyone for insight. Even if they believed him, having yet another aspect of himself that differed him from others become common knowledge was unappealing. He would have to investigate the matter for himself.

It took several months of experimentation and research, but he discovered that he had the ability to become a panther-like creature at will. This talent was indeed, unique to himself. Though he could not draw a definite conclusion, the cause appeared to be derived from the genetic tampering necessary to produce a Vulcan/Human hybrid. It was believed that all humanoids shared a common ancestry that lived billions of years ago. The geneticists had believed that if they regressed key Vulcan genetic sequences to the equivalent of their ancestors, it would be more compatible with a human's. On the surface, this appeared unlikely to work, since Vulcans descended from feline-like creatures, and humans, from apes. However, they knew what they were doing, and it had indeed worked. Though he could not prove it, it appeared his altered feline genetic sequences had resulted in in something they had not predicted: feline shape-shifting. He had no other explanation.

Spock kept this knowledge to himself. If one day, he became bonded, he would share his ability with his partner. Otherwise, no one would know. He practiced his shifting until he grew quite proficient at it. He used it to escape Stonn on numerous occasions, until the boy grew bored with fruitless chases.

Now, Spock had left Vulcan, and was enrolled at Starfleet Academy. He found adjusting to humans to be quite difficult. They were wildly emotional and unpredictable. There seemed to be no rhyme or reason or logic to any of their actions. The females were especially puzzling, inviting him to consume questionable drinks and batting their eyelashes at him one moment and walking off in a huff the next.

Spock found this distracted him from his studies. He knew if he were to succeed in Starfleet, he would need to learn to get along with humans. However, he preferred his learning experiences to come in smaller doses. So it wasn't long before he chose to travel outdoors in his panther form instead. This proved quite effective at dissuading approach, if anyone even caught sight of him. He was quite adept at stealth with all the practice Stonn had given him.

One day, Spock was ambling along in the large park for the cadets, in no hurry to go anywhere. He was enjoying the quiet solitude that his panther form afforded him. Most people didn't give him a second glance, apparently assuming he was merely a larger version of the other loose cats that roamed the campus and nearby streets. But today, for the first time, he was approached while in his cat form.

"Hey, you're pretty big there, fella," said a bright, cheerful, male voice.

Spock froze, and then slowly turned. It was a blond cadet that he recognized from his classes. Spock searched his eidetic memory for his name. Kirk.

"Wow, look at those fangs," said Kirk. "And those claws! I'm surprised no one has tried to catch you. But, you seem pretty tame." Kirk approached him slowly.

Spock dithered, torn between fleeing and indulging his curiosity about what Kirk would do next.

His hesitation made the decision for him. Kirk got within arm's reach and squatted next to him. "Hey, big fella. Where do you come from?"

Spock regarded him silently. Why did Kirk talk to him, when clearly, he could not answer? Yet, such illogic was only to be expected from humans.

Kirk reached out slowly, and Spock tensed. Nobody had touched him in this form. Nobody touched him even in his Vulcan form, except for his mother, and the occasionally brazen female.

"Hey, it's okay," assured Kirk, before giving him a gentle pet. He retracted his hand, and Spock relaxed. That had not been overly unpleasant, merely strange.

"Been here long?" Kirk asked.

Spock stared at him with such disdain that the human laughed. "Hey, I know. I'm weird, talking to a cat. If Finnegan were here, he'd never let me hear the end of it."

Resigned to Kirk's continued presence, Spock settled down into the grass. Kirk plopped down beside him. "You know, I thought with all of Starfleet's high notions and aspirations, things would be different. But it turns out there's bullies in Starfleet just like there is in Riverside."

At least this was something Spock could relate with. He wondered how Kirk dealt with his bullies, since it was doubtful he had Spock's ability to shape-shift. Spock could estimate the odds, but he did not believe that Standard had words for that percentage of a decimal.

"You've probably never been bullied a day in your life," Kirk mused. "You're the big cat in town."

If the cadet only knew. Of course, if he did, he wouldn't be speaking to him. At the Academy, Kirk never gave him a second glance. To be fair, Spock hadn't given him a second glance, either. Spock wondered why Kirk was bullied. He did not seem to stand out from his classmates in any way that he could detect.

"But, that's life, huh? It's not so bad. The Academy is great. I really feel like I've found my place in life, right here."

Spock agreed with that sentiment. They sat for the next several minutes in companionable silence that Spock found rather pleasant. He'd never been in the company of another humanoid without something being demanded of him. He wished this would happen in his biped form; however, if he conjectured his future from past data, it appeared astronomically unlikely.

"Well, I have studying to do. Maybe I'll see you again." Kirk flashed him a brief smile as he rose and departed. Spock watched him go, before stretching and heading to his dorm. He believed Kirk's idea had merit.

Though Spock caught brief glances of Kirk on campus, he did not meet up with him again until a few weeks later, while Spock again wandered in his feline form.

"Hey, I wasn't sure if I'd see you again! How've you been?" inquired Kirk, sitting down instead of coming closer. Spock hesitated, but approached him and lay down in the thick grass, eyes on the cadet. He was most curious as to what Kirk would say this time. It was much easier to interact when he did not have to guess what was expected of him in return. It was most pleasant.

"I wonder where you live. I've asked around, but not many people seem to know about you. It's pretty strange, you know? You're pretty unforgettable."

Spock had been called many things, but not "unforgettable." Despite his Vulcan sensibilities, he preened inwardly. He'd long ago discovered that emotionalism was different when he existed as a feline, and had accepted it.

"I'd take you home, if my dorm mate would let me. He'd probably just say that 'living with one goddam animal is bad enough, I don't need two of you!'" Kirk laughed. Despite the seemingly derogatory nature of the conjectured comment, Kirk appeared to enjoy the possibility. Most illogical.

"So, can I pet you, or are you still squeamish?" Kirk asked him.

Spock eyed him warily. The first attempt hadn't been too bad. He would allow him to repeat the experiment.

Kirk reached out, and, encouraged that Spock didn't tense up as much this time, he slowly stroked his back. Spock's eyes shut halfway. It was strangely soothing. Kirk repeated the motion, and then moved his whole body closer so he could be more comfortable. Spock dropped his head in the grass and allowed Kirk to pet him all over. A strange rumbling vibrated in his chest.

"Are you purring?" Kirk asked in disbelief.

Spock flicked his ears. It appeared to be the logical conclusion. Despite his embarrassment at the rampant emotionalism, he was quite fascinated by the experience. He'd never purred before.

Encouraged, Kirk began massaging him in earnest. Spock decided there was no logical reason to move anytime soon, and his eyes drifted shut. His purring increased, until his entire body vibrated with it. Then Kirk's hands left him. Spock's eyes flew open and his head jerked up in protest. He looked at Kirk questioningly.

"Gotta go. Sorry, pal. Maybe I'll see you again." With a final, gentle pat, Kirk turned and walked away.

Spock stared after him, feeling oddly bereft. Why had he stopped? What was so important? With nothing else pressing to do, he stealthily followed the cadet. He'd never used his form for information gathering before. He wasn't stalking the cadet. He was merely curious as to his next destination.

He got his answer a few minutes later. Kirk disappeared into a dorm, then came out accompanied by a female who was "batting her eyelashes" at Kirk. Spock catalogued Kirk's responses to her. Apparently, they were the appropriate ones, because the lady did not walk off in a huff, as they did with Spock. Quite the contrary, her expression only grew brighter the more Kirk talked. Kirk flashed her a big smile. Spock's tail twitched. He did not see what was so important about this female that Kirk had to end his time with Spock. Also, why didn't Kirk smile at Spock like that?

It was illogical to ask himself questions he didn't have the answers to, so Spock slunk away and discreetly changed back into his Vulcan form. If a female approached him again, he would try telling her the things that Kirk had told his companion, and observe the results. Perhaps then, he might understand.

It wasn't long before an opportunity arose. He wondered why so many females approached him, as he did not observe them behave this way with most of the other males. They often used the word "adorable" when describing him. Perhaps this mysteriously defined quality was something the others lacked? Whatever the reason, a female cadet who'd introduced herself as Nyota was now talking to him in a manner that usually led to an invitation for shared personal time. Spock recalled Kirk's lines with perfect clarity, and delivered them with scientific precision.

For some reason, this appeared to amuse the woman greatly. She covered her mouth with her hand in a highly ineffectual attempt to conceal her mirth at his expense. Spock raised an eyebrow. Though this didn't quite correlate with the response of Kirk's companion, it was, indeed, an improvement over his previous logical attempts to deal with the situation. He would continue to use Kirk's lines and observe the results.

"Oh, Spock," she gasped with a laugh. "Who taught you that?"

"I observed someone saying it," Spock admitted. "I presumed it was acceptable behavior for humans."

"Maybe if you're a playboy, like Gary Mitchell or Jim Kirk," Nyota told him.

"I do not understand this "playboy" reference," Spock said.

"It's nothing you are. That's why I like you. So, what do you say?"

Spock delivered another one of Kirk's lines that conveyed acceptance with a quirk of his brow. As he predicted, Nyota laughed outright and appeared delighted, despite her previous insistence that it did not mesh with his personality. It must not be as negative as her tone had implied. Given what he knew of James Kirk, it made sense. In an illogical, human sort of way, of course.

They ate lunch together at a café near the campus. Though Spock did not understand how to make "small talk," Nyota was unusually patient with him, for a human. Perhaps her companionship would continue longer than the others had. When they finished eating, they said their goodbyes with a vague promise to meet again. Spock walked back to the campus, quietly analyzing the interaction. While it had not been unpleasant, he still did not understand why it had seemed so important to Kirk.

Speaking of Kirk, the cadet was walking towards him on the sidewalk, a focused expression on his face as he didn't give Spock a glance. The Vulcan's brows drew together. But of course. Kirk had no idea that he and the panther were one and the same. Spock, of course, had no intentions of revealing that, but he found he did not like to have Kirk ignore him completely. So Spock did something he had never done before: he sought interaction with a human outside of educational reasons. "Greetings, Cadet Kirk."

Kirk's legs stuttered in surprise. "Uh, hey. Spock, right?" he said.

Spock fell in step beside him. Strange how different his manner was now that Spock was in his biped form. "You are correct."

"What's up?"

"I believe that is what we are here to learn," answered Spock, rather confused.

Kirk gave a short laugh. "I suppose you're right."

Silence fell as Spock searched for something to say. Though he much preferred the undemanding interplay while he was a feline, he found the opportunity to speak with Kirk rather engaging. "How are your studies progressing?"

"Oh, you know," Kirk shrugged. "It's a piece of cake, really."

Spock's brows drew together. "I fail to see how the demands of the Academy courses resemble a Terran baked food of questionable nutritional value."

Kirk chuckled again. "It doesn't, it's just one of our illogical human expressions. Oh – Hey, McCoy!" Kirk waved to a rather disgruntled cadet that appeared to be older than him. "That's my dorm mate. He promised to be my wingman."

"I was unaware that our class had progressed to simulations," Spock said in confusion.

"No, no," said Kirk, grinning. "It's another expression. It means we're going to get drinks. He's going to help me pick up women."

Spock opened his mouth to tell Kirk that he appeared strong enough to manage it himself, and then closed it. Judging by the previous flow of conversation, it was unlikely he meant it in a literal sense. He changed tact, driven by curiosity. "Is this why you are labeled as a 'playboy?'"

"Whoa, hey, who've you been talking to?" Kirk laughed. "I'm not out to hurt anyone. It's all in good fun."

By now, McCoy was within feet of them. "Hey McCoy, this is Spock. Spock, McCoy," Jim introduced him.

Spock gave McCoy a curt nod. "Cadet McCoy."

"Actually, I prefer Dr. McCoy."

"Very well, doctor," Spock agreed easily. He spoke next without thinking. "Though as a medical professional, I admit surprise that you would deem your dorm mate an animal."

McCoy gaped at him, and Kirk, strangely, howled with laughter. "Oh my god, where have you been getting this stuff about me?"

"I have heard it said at the campus," said Spock, backpedaling. It wasn't a lie.

"Your reputation precedes you, kid," McCoy griped at Kirk, recovered from his shock. "Told you should cut down on the drinking and partying!"

"Yeah, yeah. I will when you will," said Kirk, and McCoy appeared to have no comeback. "Say, Spock. Want to be my wingman too?"

Spock's brows drew together. "I am inexperienced in what you refer to as 'picking up women.' I do not believe I am a good candidate."

"Nonsense, Spock. Word has it, you're the hottest item on the campus," insisted Kirk. "Women approach you all the time!"

Spock, though confused at the terminology, could not argue with the conclusion. "Indeed."

"Heh, and you're modest, too. You'll do great!"

With that, Spock found himself accompanying the two cadets to a bar. He'd never entered one before and studied his surroundings with curiosity. He sat at the bar with them and sipped an Altair water. It wasn't long before Kirk approached a woman sitting at a nearby table and conversed with her at length, drink in hand.

"Is it true that Kirk drinks too much?" Spock asked McCoy suddenly, surprising even himself.

"He's not as bad as some, but yeah, I think he should cut down," McCoy told him, glancing at him strangely. "Why do you ask?"

"I do not know," Spock admitted.

McCoy grunted. "I know what you mean. Times like this, I don't know why I bother. But, he's not a bad kid. Don't tell him I said that."

"I shall keep your confidence," Spock promised. He found it difficult to reconcile the cocky, brash cadet in front of him with the gentle, kind, sincere side of Kirk he experienced as a feline. He found he greatly preferred the latter.

Kirk soon disappeared. Spock and McCoy made conversation in short bursts over the next hour before the doctor finally gave up and called it a night. Spock exited the bar after him, and, deciding he'd had enough of humans for the day, discreetly switched forms. He was quite undisturbed the rest of the way to his dorm.

Spock encountered Kirk in both of his forms with more frequency during the weeks that followed. His preferred interaction was while he was feline, with Kirk massaging him and telling him whatever was on his mind far more honestly and openly than he did when he believed himself observed, Spock purring all the while. Even so, a vague, unfamiliar feeling of guilt rose in Spock. He knew that his relationship with Kirk had progressed to the point that his behavior towards him was considered dishonest. Yet, how could he tell him the truth? A time or two, Spock opened his mouth to tell him, but nothing came out. Why was it so hard? He had never lost control of his faculties like this before. Also, why did he find it increasingly difficult to suppress his annoyance at Kirk's behavior, especially when he left him to pick up women?

Spock found himself turning to McCoy for advice when he encountered the doctor without Jim tagging along. "Doctor. I have something of a sensitive nature I wish to share with Jim," he admitted. Jim had finally convinced him to start using his first name. "He may react negatively. How do you suggest I approach him?"

McCoy eyed him speculatively. "I'll tell you something. You don't have anything to worry about."

Spock raised a brow. "Why do you come to that conclusion?"

"Look," said McCoy grumpily. "I ain't blind to the way you two look at each other. If you approached him, I think he'd actually go steady for once. It'd be a nice change."

"Go… steady?" Spock inquired, very confused. What did this have to do with his feline form? Clearly, the doctor had made a false conjecture.

"Uh, you know. Court for a long period of time. Which for Jim, is more than a week," McCoy said. "Whatever you Vulcans call it. Bonding rituals?"

Comprehension dawned. "You believe me to be romantically interested in Jim?"

"Well, it's pretty damned obvious. Every time he leaves you for a woman you look ready to snatch him back. And he acts nervous around you, like he's scared to approach you about something he wants to say."

Spock had been so busy with that very dilemma he'd failed to notice any mirror behavior in Jim. "Fascinating."

"Yeah, well, you've heard my two cents," McCoy grumbled. "I've got to get to class."

Spock watched him go. His conversation with the doctor had left him more confused, not less. He could not deny the evidence that backed McCoy's assertions, yet, how did this factor into his feline problem? How could he inquire into a possible romantic relationship when also admitting to deception? It was most illogical, even for a human. Yet, Spock knew that the more he delayed, the more the situation would deteriorate. He would confront Jim at the first opportunity, despite the strange sinking feeling in his chest.

He planned the conversation carefully. He waited until his dorm mate left for the weekend to visit his grandparents. Then, he invited Jim to join him in his room to talk. Strangely, Jim appeared as nervous as he was. If McCoy was to be believed, this was because Jim was interested in a romantic relationship. It did not make sense to him, especially since he never seemed nervous about his other romantic conquests, but he yielded to the doctor's expertise on the matter.

Spock gestured for Jim to sit down on the bed, before putting his hands behind his back. Jim sat down, scratching his neck nervously.

"Jim, I have been dishonest with you," Spock said without preamble.

Whatever Jim had been expecting, that wasn't it. He stared at Spock in confusion. "What?"

"I hope you will forgive the dishonesty and continue to associate yourself with me."

"Hey, it's okay, Spock," said Jim. He couldn't imagine what the uptight Vulcan would consider "dishonest." Maybe that his favorite color was purple instead of blue? "What is it?"

"I believe it would be better to show you." Spock swallowed and straightened further. Then he closed his eyes, and shifted. When he opened them, Jim had a hand over his mouth. Since his feline form did not facilitate communication, he quickly shifted back. "What are your thoughts on the matter?"

Jim still appeared unable to speak. Spock's brows drew together. "I realize this is quite unusual. I have never told anyone about my ability. However, considering our relationship, I believe I owed you this knowledge."

"It's been you all along," Jim said quietly, for once not giving away what he was feeling. Spock thought it was an inconvenient time for him to gain that ability.

"Affirmative. I prefer to wander the grounds, undisturbed, for peace of mind."

"You don't like getting mauled all the time by illogical humans," Jim mused, his face blank.

"While I find the imagery to be graphic, it is not a completely untruthful parallel," Spock admitted. "However, I… enjoyed our time together in my feline form." Spock studied Jim's averted face. "Does my ability disturb you?"

"No, no, it's totally badass. You're like, Batman – or, Catman," Jim gave him a brief grin.

"Yet you do not appear pleased," Spock observed. "I assure you, it was never my intent to deceive you. When we first met, I did not predict that you would continue to associate yourself with me in the manner that you have. I prefer to keep my ability to myself."

"Spock," Jim said, appearing to struggle for words, which was unlike him. "Humans, ah, sometimes act differently in private than they would if they knew someone else was around."

"Indeed," said Spock. "I have observed that in you. However, I see no problem. You have accepted how I am different; I see no reason not to return the gesture. Also, I found your behavior with me as a feline preferable."

"You did?" questioned Jim, shocked, meeting his eyes.

"Affirmative. Your manner was kinder, more open, intelligent, and sincere. In addition, your skills as a masseuse are unparalleled. Have you formal training?"

"You didn't think it was, well, weird?" Jim asked, remembering with sharp embarrassment some of his more, ah, personal comments.

"Negative. I found your verbal commentary to be quite engaging."

Jim smiled slowly, Spock's earlier comment coming back to him. "I have never been trained as a masseuse. But I had a cat at the farm, and he liked being petted that way." His grin widened as he remembered how Spock always became a big puddle of purring fur whenever he touched him. It was such a stark contrast to the seemingly untouchable, emotionless Vulcan. So, Jim wasn't the only one who behaved differently when he believed himself unobserved. Maybe there was hope after all.

"You have forgiven my deception?" Spock prodded, now that Jim's countenance appeared positive.

"Well, it's pretty embarrassing," Jim confessed. "But yeah. It's cool."

"Good." They were silent for a bit, slightly awkward. What now?

Jim asked questions about his shape-shifting, which Spock answered to be best of his ability, detailing when it began and the suspected cause. Jim listened raptly, his manner softening into the one he'd used with Spock's feline form. Spock found the change quite pleasing. He found he did not want to share it with anyone. That would require taking the next step, as McCoy had presumed he'd intended to do. Yet, now that he was faced with making a move, he found his vocal cords, once again, mysteriously inoperable.

"You know," said Jim, his grin turning rather manic. "We could have a lot of fun with your shape-shifting."

"To what are you referring?" asked Spock.

"Take McCoy, for example. He's so much fun to prank." Jim thought fondly of a few fast ones he'd pulled with his friend, which, to this day, McCoy hadn't realized was him. It was hilarious. "We could sneak you into the dorm, and you could leap out at him or something."

Spock imagined the scenario. "Is this not as deceptive as the behavior I exhibited with you previously?" He did not want to make the same mistake again.

"This is different. This is for fun," said Jim, but he didn't press further.

"There is another matter," Spock said, now that his vocal cords were operable again.

"What?" Jim asked softly, his face growing serious as he sensed the shift in Spock.

"It has come to my attention that our relationship has the potential to become more. Is this correct?"

"Meaning?" Jim asked, anticipation rising.

"Meaning that you will engage yourself with me rather than females. Is that agreeable?" Spock waited tensely for his answer. It was possible McCoy had been mistaken.

Jim gaped at Spock's bluntness. "Yes, yes it is."

Spock offered two fingers, his eyes soft. Jim stared at them in question. "It is a Vulcan kiss." Jim's fingers met Spock's. Spock allowed himself a tiny smile at the dawning joy on Jim's face. Jim had accepted him, even knowing everything about him. He wasn't alone anymore.

Important! This is my preferred ending to his story. The next chapter is an alternate ending that I didn't like as much, but seemed a shame to delete, so if you want a longer version of this story, read on. The italicized sentence starts my preferred ending, so mentally delete that sentence and everything after that if you're reading the next chapter.

Also, while I have your attention, if you are interested in reading my stories too mature for this site, check them out at Ao3. (Archive of Our Own) There is at least one long story there that is not posted here.