A/N: Thanks for the comments, guys! I'm glad to see readers willing to give a crazy rare pair a chance!

We Might Be Radioactive
Chapter 3

"Your enzyme increased the ratio of pyrrolidine," said Peter as he scrolled through the latest report from Bruce's computer. "It changed what would normally be an ampullate strand into more like an aggregate. Made it hygroscopic."

Bruce hummed thoughtfully from the next desk over. "A side effect of increasing the amount of potassium nitrate to prevent it from denaturing. But how to affect one and not the other..."

"Maybe if we introduced the enzyme under heat, it would prevent it from forming into proline...?"

"Hmm. Interesting."

Peter glanced over at him. For the third night in a row he'd come back to the tower to mull over the problem of his webbing. Not that it was even a problem, really - his webbing had served him perfectly well, as far as he was concerned, and he wasn't convinced that extra MPa would make that much of a difference. Still, he enjoyed the challenge. He'd spent most of fourth and fifth period reading up as much as he could on spider silk, complex proteins, synthetic enzymes and anything else that seemed useful. It was far more interesting than his school work and he felt a little thrill of victory whenever Bruce got that little gleam of approval in his eye.

Despite its tragic ending, Peter had enjoyed his short time working with Connors. It had helped him feel useful and valued in a way skinny nerds like him seldom experienced in high school. More than that, knowing that Connors had at one time worked alongside his father had given him a closeness to his long-departed parents. During those short days he had often wondered if he might have worked alongside his father in a similar manner, if fate had been kinder.

But working with Bruce didn't remind him of Connors or his Father. Bruce was too much of a mystery. He was easy and light-hearted, refreshingly so, but sometimes Peter caught a hint of tension beneath his slow smile, like a wire drawn taut under his skin. He watched Peter out of the corner of his eye as if he were the hungry spider watching a fly in its web, waiting for a lowered guard or an exploitable mistake. Sometimes there was only fondness. Sometimes there was something else, something childish and hopeful, and Peter couldn't help but think it was the way his six-year-old self had looked to potential friends on the playground.

Which was kind of strange coming from a forty-year-old man, but Peter wasn't about to complain.

"Spiders create different varieties of webbing by accessing different glands," said Bruce as he tapped at his keyboard. "I wonder if we might get the properties we're looking for by following their example, and using more than one cartridge at a time."

Peter rocked in his chair. "Sounds interesting, but maybe not as practical. I have to use this stuff on the fly, you know."

"Oh. Right." Bruce chuckled. "Practical application: the enemy of speculative science."

Peter laughed with him. "I'm going to grab a snack," he said. He pulled a rolled up bill out of the back of his mask. "I came prepared this time."

"Skittles," Bruce replied with a smirk.

Peter hopped into the hallway. As he stood in front of the vending machine he thought of the revelations from the night before. "Human genome," he muttered to himself as he punched in the various letters and numbers. It hadn't left his mind, the fact that Bruce had talked about reversing mutation. Just thinking about it made his palms itch for a wall to hang off of. All through the day he had considered telling Bruce the truth about his own unique circumstances, but that would likely entail revealing his identity, and he wasn't quite up to that yet.

Peter returned with a handful of junk food and pulled his mask up enough for a drink of sweet caffeine. He was about to suggest another strategy when he noticed Bruce staring at him, but not in the hungry, fond, or hopeful way Peter was used to. "What?"

Bruce brushed a hand over his mouth. "What happened?"

"Hm?" Peter touched his jaw and finally remembered the bruise stretching down the corner of his mouth. "Oh yeah - I got sucker-punched by a fire escape on my way over. This punk pulled a knife on me, and when I went to dodge - wham. Kind of embarrassing." He gave it a brief rub and then took another drink. "Doesn't hurt anymore, though."

Bruce continued to stare a moment longer, putting a self-conscious itch between Peter's shoulder blades. It wasn't that Bruce was concerned - he had seen enough side-eyes from Gwen and Aunt May that he knew what "I wish I could tell you to stop" looked like. It was something else. It was as much a mystery as the goop they were making out of his webbing.

Bruce ripped open his Skittles, but only ate one before turning back to his computer. "Tough work, being a super hero," he said.

"Yup." Peter stole a Skittle when Bruce wasn't looking. "Goes with the territory."

"You might consider getting better protection than spandex...?"

Peter chuckled. "What, you don't like the suit? You had your hands all over it the other night."

Bruce had been reaching for the candy when he coughed sharply, and he spilled a handful across the desk. His glare said "I told you so" but Peter only shrugged. "The suit is fine," he said, a little red in the face as he tried to herd the Skittles into a huddle. "But there is something to be said for Kevlar."

One of the Skittles escaped and clattered across the floor, and Bruce rolled his eyes. Rather than chase after it he went back to his computer. Peter smirked to himself as he retrieved the wayward orange. "You know, there's a certain spider that produces silk stronger than Kevlar." He gave the Skittle a blow and figured the five second rule applied.

"Caerostris darwini," Bruce supplied. "Darwin's bark spider."

"Huh." Peter began nudging the Skittles into an all too familiar formation. "So did you become an arachnologist overnight?"

"Just trying to keep up with you," Bruce said with a smirk.

Peter tongued the inside of his cheek, pleased. "Aaaaand, nitrogen," he finished triumphantly. "There it is. Our nemesis."

Bruce cocked an eye, and he shook his head at the sight of Peter's Skittle-molecule. "Pyrrolidine. Whatever are we going to do with you?"

Both were quiet and contemplative for a moment, and then Peter stole one lime-flavored carbon atom from his molecule. Bruce narrowed his eyes and nudged the remaining "atoms" into a new structure. "Isopropylamine," he muttered, smiling to himself as if proud that he could identify the new formula so easily. And then Peter almost literally saw the light bulb appear over his head: his eyes lit up, his spine straightened, and he flashed Peter a secretive grin. "I know what we're going to do with it," he said.

Peter straightened with him and felt a contagious prickle of eagerness. "You do?"

Bruce set his foot against Peter's chair and pushed, sending Peter skidding away from the computer so he could take his place. "Isopropylamine is used as a regulating agent in certain plastics," he said as he began typing furiously. "And other coating materials, like rubber..."

Peter grabbed at the desk to keep from sliding too far away. "I think I see where you're going," he lied, "but we can't just replace the pyrrolidine with iso-whatyousaid by plucking out carbon atoms."

"No, no, no, it just inspired me." Bruce slid his tongue along his teeth - it was the most animated Peter had seen him, and it was amusing to watch. "We're switching gears, here. Less web-slinging, more..." He drew the word out into a hum as he hurried to complete his inputs. "Mooorrreee...this."

Bruce pushed away from the desk and waved for Peter to come back. Peter did so, stealing another handful of Skittles on the way, and sucked on them thoughtfully as he looked over Bruce's new project. It took him a moment to realize what he was looking at: their goop formula represented not as a string, but as a woven, structured web in lines like fabric.

"Okay," Peter said slowly. "Which gear did we switch to?"

He was a little worried that Bruce would be irritated in having to explain, but he needn't have been; Bruce was all too eager. "With the webbing now, the main limitation is its practicality, as you said. Getting the silk to spin at a precise viscosity and tensile strength is an incredible challenge, especially on demand. However, there are ways to treat the silk and alter its properties in a more controllable setting, without the constraints of field use, after it's spun. The current formula increased the tensile strength enough that if we found a way to delay the denaturation process even further, it could be worked into...well, a textile, I suppose."

Peter finally caught on, and he was glad that Bruce wouldn't be able to see his feet kick excitedly under the desk. "Like Kevlar?"

"Like this."

Bruce pressed two fingers to Peter's right shoulder and pulled, drawing them over the rubber ridges that decorated the spandex. He traced a particular strand all the way from one shoulder to the other, sending a little shiver cascading down Peter's spine. "How often do you go through suits?" he asked.

Peter started to answer, but was distracted when Bruce paused to rub his thumb against a tear in the costume just above his left shoulder blade. "This is...the third. Or fourth, I think." He chuckled and wished it didn't sound so thin all of a sudden. "Sometimes I have to patch in sections. It's durable, but like you said, being a super hero is rough. It's a good thing I found a site where I can get a good deal on materials, because I do a lot of repairs."

"If we can create for you a...an exoskeleton," Bruce said, sounding pleased with himself, "it would help the suit last longer. It might even dull a knife blade." He laughed. "Though I'm not sure it'll help much against fire escapes."

"Ha, ha." Peter leaned back into the pressure of Bruce's hand against his shoulder. It was heavy and warm, and oddly comforting. "But that still doesn't solve our problem of the web being sticky and gooey."

"That can be treated once it's been fired," said Bruce. "Maybe if we sprayed the webbing onto a glass surface to form a sheet, and then dehydrated it, or else treated it with some kind of sealant. It doesn't have to come out of the cartridge perfect if you're not using it to swing about, right?"

"I guess not." Peter snatched up his Coke for a long drink as he tried to consider every angle. "And it's flexible and lightweight enough that it shouldn't hinder me. The hard part will be fixing it onto the suit." He craned his head back. "You're not going to stitch it on the suit with me in it, are you?"

"Actually, I'm thinking of getting permission from Tony to sic JARVIS on you," Bruce said. "Then we can get a full body scan."

Peter arched an eyebrow beneath his mask. "Full body scan," he repeated. "Sounds kind of kinky."

It really wasn't the way to be talking to a man twenty years his senior, and Peter still wasn't sure where his gall was coming from, but when Bruce gave the back of his neck a subtle squeeze it didn't convince him he wanted to stop. "We are talking about Stark tech, here," Bruce teased back.

"Yeah." Peter glanced around the lab again. "All this cool stuff, all to yourself. After dark. Mr. Stark must like you a lot to let you play with his toys like this."

Bruce let go and returned to his own chair, to Peter's slight disappointment. "It seems he does, though I couldn't tell you why. I haven't even known him that long." He pushed his glasses up on his forehead and picked through the rest of Peter's snacks. "He'll be back on Sunday, by the way. If you're lucky, you might even get to meet Ms. Potts."

"Ms. Pepper Potts?" Peter tugged his mask down before Bruce could see his boyish smile. "She really seems like something. I mean, not that I'd know. But, you know. From the interviews."

Bruce smiled sideways at him. "You don't have a thing for red-heads, do you, Peter?"

Peter laughed self-consciously. "No, I'm just saying, she seems...capable. You'd have to be to be with Tony Stark, right?"

"That she is."

Peter watched as Bruce opened a bag of potato chips. A sudden curiosity gripped him. "You married, Bruce?"

Bruce showed off his bare left hand. "Nope."

"Girlfriend?"

"No." Bruce's expression twitched. "Not exactly."

Since they seemed to be taking a break, Peter leapt at the possibility of some more personal information about his strange new friend. "Not exactly," he echoed. "That sounds like, 'there is someone, but she doesn't know I exist.'"

"No, it's not..." Bruce scraped the back of his hand across his mouth, smearing away a flash of irritation. "It's not like that, really. I had someone. But I screwed that up long before my work got in the way, and now..." He shrugged helplessly. "It is what it is, I guess."

Peter scooted a little closer. "So you're saying I shouldn't ask you for relationship advice?"

"God, no." Bruce surrendered a self-deprecating laugh. "It's a Friday night and I'm in here, aren't I?"

"You're not alone," said Peter. He had meant it as a joke, but when Bruce's eyes flickered to him, warm and grateful, it felt like something more.

"What about you?" asked Bruce. "Do you have a 'not exactly?'"

"Well..." Peter pulled his feet up on the chair. "It's complicated."

"I'm not going anywhere."

Peter hesitated, but it was difficult to hold it in when Bruce was watching him so expectantly, without judgment. There might not have been anyone else he could tell. "There's a girl," he said, and immediately the sober tone in his voice erased Bruce's grin. "A girl I like. Liked. I'm not sure now." He fidgeted. "She's knows about me being Spider-Man, and for a while that was cool, you know? Having someone to talk to about it. And she's gorgeous."

"Of course," said Bruce, sounding somewhere between amused and sympathetic.

"I don't know if things would have worked out, if everything had gone down differently," Peter continued. "But things went...wrong. Really wrong." Peter's throat tightened, and the only way he could think of to fight through it was to surrender the truth. "Her dad's dead because of me. I know she doesn't blame me - she says she doesn't - but it's not the same, being with her now. I can't..."

Emotion got the better of Peter, and he had to stop, frustrated that he'd let things go so sour so quickly. He rubbed his face through his mask, but before he could figure out a way to continue, Bruce beat him to it.

"You can't look at her anymore without feeling that guilt," Bruce supplied grimly. "That pit deep in your stomach, telling you she's better off without you. Might even be better off if you'd never met at all."

Peter swallowed; he felt it. "Yeah."

Bruce looked away, his gaze losing its focus - locked on some distant memory, maybe. He was quiet for a long moment, took a breath, and then hesitated again before finally admitting, "I know what you mean. There was a time I thought that maybe the whole world would be better off without me." His words were chilling, but then he smiled, slow and sincere. "And I was proved wrong."

He turned to face Peter. "Don't ever sell yourself short, Peter," he said, meaning it. "I don't know if you can work things out with your friend, but even if not, you have a lot to offer others." His lip quirked. "Especially women, I'm sure."

Peter groped after a response and came up wanting. His chest was tight and for the first time in Bruce's company he felt young - desperately young. He didn't know what to make of the wise look Bruce had fixed on him. He cleared his throat. "Thanks."

Bruce took in another breath and forced a chuckle. "Well. That got serious fast, didn't it?"

Peter laughed, expelling his remaining tension. "Yeah, sorry. A pair of nerds commiserating over their failed love lives? Could we be more of a cliché?"

"Tony would be ashamed of us," Bruce agreed. A computer two rows over began to beep, and Bruce pushed up from his chair. "I know what he'd say, though: that we both just need to get laid."

Even with his mask firmly in place, Peter was grateful for Bruce's turned back as heat crept up his neck and ears. He struggled back several virginity-revealing responses, in the process missing his opportunity for a sharp comeback. But saying nothing was even weirder, so after a few beats he finally blurted out, "Are you waiting for me to volunteer?"

Bruce laughed. "Only if you promise to keep the suit on," he tossed over his shoulder.

"Oh, wow." Peter grabbed for his drink again. "Getting kinkier all the time up in Stark Tower. This is going to be my Friday night destination of choice from now on."

Bruce continued to chuckle to himself as he replaced his glasses and checked on the computer that had sounded. His expression darkened, and with a few quick keystrokes he closed whatever program had been running. "Let's get back to work," he suggested as he returned. "We can at least toss a few more ideas around before it gets much later."

"Sure." Peter finally sat up in his chair properly, eagerly to get his mind back on more structured topics.

They worked for another hour, mostly just talking about the possible processes they could use on Peter's new suit accessory. Peter noticed that Bruce was becoming touchier - if he passed behind Peter he would set a hand on his shoulder, sometimes boldly, as if having to prove he was capable of it. Peter wasn't sure he understood the significance, but he felt it, and was happy to let Bruce have it.

When Bruce followed him to the window to see him off, Peter turned back, half perched on the sill. He still had his mask on and wasn't ready to change that yet, but he hoped Bruce understood his sincerity through it. "Hey," he said. "I don't know what your deal really is, but I just want to say...you were wrong. I think the world could use a lot more Bruce." He chuckled. "Like, a lot more."

Bruce smiled warmly. It was almost embarrassing, how easy it was to see what those simple words meant to him. "Thank you."

Peter sailed off, feeling proud of himself.

As soon as Peter was gone, Bruce returned to the computer and called up the results of the test he'd been running for most of the day. They were negative: not a viable solution, so it said. Even Stark's super computers didn't think any amount of gene therapy could dull the Hulk.

Bruce shut everything down and returned to his guest suite above. He told himself not to be disappointed. He hadn't really believed the answer was in tampering with his DNA even with the recent advances in technology. But it was still another closed door. One by one they were shutting before his eyes: radiation treatments, pharmaceuticals, environmental changes, organic and synthetic enzymes - science was running out of suggestions. Before long he would be resorting to acupuncture.

Bruce flopped into bed and sighed, stretching out on his back. As he stared at the ceiling, trying to think of new options, he was interrupted by the memory of Peter's parting words. He closed his eyes and let them filter through him, taking an inordinate amount of satisfaction from that brief but meaningful expression of acceptance. Peter didn't know him, didn't know his "better half." He had no idea what Bruce was capable of and what he risked just by spending time in Bruce's presence. His words were well-meant but they were ignorant; they should not have affected Bruce, but he couldn't stop thinking about it.

Because maybe Peter was right. Maybe the world could do better than simply tolerate Bruce Banner - maybe the world was better off with him in it. He had made a mess of Fury's Hellicarrier, but in the wake of that failure he had become stronger and fought alongside new peers, saving lives and protecting all of Earth. He was more than worthwhile, he was a hero, and every day he spent absorbed peacefully in his science gave him greater confidence. There were people who respected him, liked him and his company, even among those who knew what he was and what he'd done in his past. For the first time in years he felt real hope, that he needn't be working on a way to relieve himself of the Hulk, only that he need trust himself to let the creature out when needed, and call it in again when the dust cleared. He could live like this and not be afraid anymore.

Ridiculous, that playing science with a man likely a decade his junior made it so easy to imagine. "Peter," Bruce mumbled. "Who the hell are you anyway?"

Bruce still had no idea, though his imagination had supplied him with a wide variety of possibilities. All through the day he had speculated, trying to picture who lay beneath all that spandex and sarcasm. Peter was rough, and playful, and young, but he was talented, even if he still had a lot to learn. Was he an ambitious grad student? Secretly an Oscorp employee, which would explain his access to the webbing solution? Government sponsored after all? Bruce should have been wary, but he had the feeling that army spies didn't joke about sex in spandex suits, and if they did, maybe he ought to get back on the radar.

In the dark of the bedroom, Bruce let his mind drift. He wondered about the man beneath the suit, proven to be human only through the briefest glimpses of wide, red lips. He remembered the feeling of the cool fabric beneath his fingers and imagined slipping beneath it, peeling it from Peter's long body inch by inch. He dared to fantasize about sucking caffeine and sugar from Peter's grinning mouth and could almost taste wry laughter against his tongue.

Bruce took a deep breath and slipped his hand beneath his waistband, tentatively stroking his half-hard cock. It had been a long time since he'd allowed himself this. In the years since his accident he'd spent several uncertain he was capable of excitement for its own sake, and fear more than anything had prevented him from even private pleasures. But tonight, he felt good. He knew better than to think his banter with Peter to be anything more than merely that, but just having that connection to another person - someone clever and quick-tongued and able-bodied - put hope in his chest and arousal in his blood. He could have a lover like Peter. He deserved it, and his confidence spurred him on, until he was stroking in earnest.

He wanted Peter wrapped around him. Shamelessly he imagined cool, ridged spandex sliding over his naked skin, and he gasped, planting his heels in the mattress so he could thrust into his closed fist. He could almost feel slender fingers gliding over his body and between his thighs, the quiet rush of breathless laughter against his ear. Even when his heart began to pound he ignored the old warnings, determined to have his moment. He licked the salt from his lips and moaned with the pleasure he'd denied himself for too long. His body was his. He could command and release it at will, he was sure of it, and there was no reason to fear losing himself in even his most intimate moments.

Bruce tensed and came suddenly, his back arching off the mattress as he surrendered to a swift and stuttering orgasm. With low, pleased murmurs he squeezed every drop from his overly sensitive cock and then laughed. As foolish as it seemed, he hadn't been as proud of his climax since his first, decades ago. Just knowing that he could do this much with no fear of warning bells and police action spurred him to boyish elation, and he laughed.

He slept better than he had in years.