"he's either a popsicle or a furnace"
Natasha sighed as she watched Peter shiver on the couch, even though he was bundled up in multiple blankets. Ever since the spider bite that gave him his powers, he had struggled to regulate his body temperature. Small spiders couldn't thermoregulate well, and that trait had unfortunately been passed on to Peter.
"Still cold, маленький паук?" Natasha asked, using the Russian term of endearment she had adopted for him.
Peter nodded, teeth chattering. "Y-yeah. Can't seem to g-get warm."
Natasha's heart ached for him. She knew how miserable the cold could make you feel. An idea struck her. "Wait right here, I'll be back in a minute."
She headed to the common room kitchenette and warmed up a mug of milk in the microwave. After steeping a tea bag in it for a few minutes, she retrieved the warmed milk, perfect for helping raise Peter's core temperature.
"Here, drink this," she instructed, handing Peter the mug.
He gratefully accepted it, sighing in contentment as the warmth seeped into his hands. "Thanks, Nat."
She smiled as he took a cautious sip, not wanting to burn his mouth. His eyes lit up at the sweet, creamy taste.
"Mmm, this is really good!" he said before taking a larger gulp.
"An old Russian remedy for the cold," she told him, feeling a swell of satisfaction at his obvious enjoyment. Maybe this would finally help the poor kid get warm.
As Peter drained the last drops, he set down the mug and burrowed back into the blankets. "That hit the spot. I actually feel kinda warm now."
"Good," Natasha said, playfully ruffling his hair. She was rather fond of the boy who had become like a son to her. His sweet nature and good heart had melted her hardened one long ago.
Just then, Tony strode into the room, making a beeline for the fridge. He pulled out a soda and popped the tab, taking a long swig.
"What's the kid all bundled up for? It's like 80 degrees in here," he commented after noticing Peter's blanket cocoon.
Natasha shot him a pointed look. "Thermoregulation issues, remember?"
"Right, right, spidery side effect," Tony said. He walked over and felt Peter's forehead, frowning. "Hmm, you do feel a little chilled. Did Nat's hot beverage help any?"
Peter nodded. "Yeah, I'm actually feeling really warm now. Like, kind of hot."
He pushed the blankets off, revealing his flushed cheeks. Natasha grew concerned. Maybe the milk had worked too well.
Just then, Steve and Bucky entered the room, freshly showered after training. Steve's eyes immediately landed on Peter's overheated state.
"You okay, son? You're looking a little red," he said, laying a hand on Peter's forehead. "You feel very warm."
"I'm kinda hot now," Peter admitted. "Nat made me some warm milk for my spidery coldness, but I think it heated me up too much."
"Poor kid can't regulate his temperature worth a darn. He's either a popsicle or a furnace," Tony sighed.
Bucky frowned, his protective instincts kicking in for his surrogate nephew. "Here, let's get you cooled down." He grabbed a water bottle from the fridge and handed it to Peter. "Drink up, spider-punk."
Peter smiled at Bucky's use of his nickname for him as he gulped down the refreshing water.
Steve found a washcloth and wet it with cool water from the sink, gently dabbing Peter's face and neck to bring his temperature down.
Soon, Peter sighed in relief. "That's better, thanks Uncle Steve, thanks Uncle Bucky."
Natasha still looked troubled. Getting his temperature right seemed nearly impossible with his unique physiology. What he needed was someone who could monitor it for him...
As if reading her mind, Friday's voice sounded over the room's speakers. "Mr. Stark and Dr. Banner have been working on thermoregulation technology specifically tailored to Peter's enhancements. They're waiting in the lab whenever Peter is ready for a fitting."
Tony snapped his fingers. "That's right! Come on down to the lab, kid. We'll get you all hooked up."
Peter's eyes lit up. "Really? That would be awesome!" He jumped up from the couch, ready to follow Tony.
Steve gently stopped him with a hand on his shoulder. "Hold up a sec, let's get you back to normal first. Still feeling overheated?"
"No, I'm okay now," Peter assured him.
"Alright then. Lead the way, Tony," Steve said with a nod.
The four of them headed down to the lab, where Bruce was just finishing prepping the specialized tech.
"Hey Peter, we think this will help prevent any more temperature fluctuations," he said, holding up what looked like a high-tech fitness watch. "It monitors your vitals in real time and activates heating and cooling elements as needed to keep your core at ideal homeostasis."
"Whoa," Peter breathed out, eagerly holding out his wrist. Bruce secured the watch and typed a few commands on the holoscreen.
"There, it's calibrated specifically for your unique physiology. How does it feel?"
Peter's eyes widened in wonder. "It's perfect! I can't even really tell I have it on. Thanks, Dr. Banner!"
"Our pleasure, kiddo," Tony said, ruffling the boy's hair. "Can't have my protege turning into a popsicle on the job."
Over the next few weeks, the watch proved incredibly effective at maintaining Peter's ideal body temperature. No longer did he shiver constantly or randomly spike fevers that left him weak and fatigued. He could finally regulate like a normal human.
Well, a normal human with spider-powers, at least.
The only hiccup came during a mission when Peter took a hit that disabled the watch's cooling system. Unbeknownst to him, his core temperature began steadily rising as he fought alongside the team.
"Good job webbing up those hostiles, Spider-Man. We've got this area secure," Steve reported as Peter swung down to regroup.
Peter landed a bit shakily, feeling strangely weak and lightheaded. He stumbled, bracing himself against a wall.
"Whoa there, you alright?" Sam asked, rushing over and gripping his shoulders to steady him.
"Yeah, I...I'm not sure..." Peter mumbled, before his knees buckled. Sam quickly caught him before he hit the ground.
Steve ran over, panic rising as he saw Peter's flushed, dazed state. He touched his hand to the boy's forehead.
"He's burning up! Tony, his watch must be malfunctioning."
Tony hurried over and scanned the watch with his gauntlet. "The cooling system took damage in the fight. His core temperature is spiking fast!"
Natasha felt her heart seize. Not again. "We need to get him cooled down stat, this looks like heat stroke." She began shedding his outer layers to help bring down his temperature.
Steve swiftly scooped Peter's limp form into his arms. "Back to the jet, now! Sam, crank the AC."
They rushed back to the quinjet, laying Peter on a bench and surrounding him with ice packs. Natasha cradled his head in her lap, tenderly brushing the hair back from his sweat-slicked forehead.
"Shh маленький паук, you're okay. We've got you," she soothed.
As the jet lifted off, Bruce set up an IV to hydrate him and administer fever reducers. Peter's eyes fluttered open, hazy and confused.
"Wha...what happened?" he rasped.
"You overheated, sweetheart. But we're getting you cooled down now," Natasha said gently.
Peter's eyes cleared a bit as he focused on her. He gave a weak smile. "My hero."
Natasha huffed out a relieved laugh. "No slipping into a coma on my watch, baby."
The medication quickly brought his temperature back down to safe levels. By the time they arrived back at the compound, the color had returned to his cheeks and he was sitting up on his own.
Bruce and Tony thoroughly checked him over in the med bay to be sure he was out of the woods. Once given a clean bill of health, he was finally allowed to get some rest.
Natasha entered his bedroom later that night to check on him before turning in herself. She was surprised to find the lamp still on, Peter sitting up in bed reading.
"Can't sleep?" she asked, sitting on the edge of the mattress.
Peter shook his head. "Not really. Still feeling kind of amped up after today, I guess."
Natasha studied him for a moment. "Want to talk about what happened?" she asked gently.
Peter's eyes dropped to his lap. He fiddled with a loose thread on his comforter. "I just...I thought I was past stuff like this. The watch was supposed to help me regulate better. But I guess I still can't control my own body temperature."
"Oh Peter," Natasha sighed, brushing a few strands of hair off his forehead. "What happened today wasn't your fault. Your body was just reacting to extreme conditions. We should have been monitoring the watch's performance closer during battle. And we'll improve the tech so this doesn't happen again."
She tilted his chin up to meet her gaze. "But none of us expect you to instantly master something so complex. These sort of abilities take time to get a handle on. You shouldn't be so hard on yourself, маленький паук."
Peter managed a small smile at Natasha's use of the familiar Russian nickname. "I know, it's just...it's frustrating sometimes. This spider stuff always complicating things." His eyes took on a haunted quality. "Like when I first got my powers and didn't realize I couldn't thermoregulate. I almost..."
His voice broke off as he shuddered at the memory. Natasha's heart twisted. She knew this had been weighing on him. Wordlessly, she gathered him into her arms. Peter went willingly, tucking his head under her chin like a much younger child. She stroked his hair as she rocked him gently.
"Do you want to talk about what happened that day?" she asked softly.
She felt him nod against her collarbone. Natasha continued carding her fingers through his curls, providing a soothing rhythm for him to cling to as he gathered the strength to share his experience.
"It was about a month after the spider bite," he began quietly. "Everything was still so new and overwhelming. The senses, the strength, all of it."
He took a shaky breath before continuing. "It was late fall, and New York winter was setting in quick. But I didn't really think anything of the dropping temperatures at first. I mean, I never used to feel the cold that sharply before the bite."
Peter burrowed deeper into Nat's embrace as the memories overtook him. "But that night, I was out way later than usual on patrol. Karen had to keep reminding me it was past 3am on a school night. But I wanted to stay out just a little longer."
His voice grew softer, laden with guilt. "I started feeling really tired all of a sudden. And so, so cold. It hurt to even move. I managed to wrap myself up in an old hoodie I found in a dumpster. But I was still shivering uncontrollably."
Natasha tightened her arms around his trembling frame, hoping to impart some warmth from the past to his body in the present.
"I barely had the energy to make it back home," Peter continued, voice distant as he relived that horrible night. "I crawled in through my bedroom window and just sort of collapsed on the floor. I knew something was really wrong because I couldn't seem to warm up no matter what I did."
His breath hitched on a sob. "May found me passed out and nearly hypothermic the next morning. I had to spend a week in the hospital recovering. It was...really scary."
Peter finally lifted his head to meet Natasha's gaze, eyes bright with unshed tears. "If May hadn't found me when she did, I...I probably wouldn't have..."
Unable to finish the thought, he buried his face in her shoulder again. Natasha felt her own eyes mist over. Her fierce, protective anger at his suffering warred with an aching sadness.
"Oh маленький паук," she murmured, voice thick with emotion. "I'm so sorry you went through that. But you're safe now. We've got you."
She placed a gentle kiss to the top of his head. "Thank you for telling me. You know you can always share these kinds of things, right? No need to carry the weight alone."
Peter nodded, scrubbing the tears from his eyes. "Yeah, I know. It just feels really good to get it off my chest." He gave her a tremulous but grateful smile. "Thanks, Nat. For everything."
Natasha ruffled his hair, giving him a playful wink. "Of course, baby. That's what I'm here for."
Peter laughed, the last bit of lingering darkness dissipating at the familiar nickname. He stifled a yawn, emotional exhaustion finally catching up with him.
Natasha gently guided him to lay down, pulling the covers snugly around him. She ran her fingers through his curls, lulling him towards sleep.
"Get some rest, Peter. Everything's going to be just fine. I'll make sure of it," she promised softly.
His eyes blinked heavily, already drifting shut under her soothing ministrations. "Love you, Mom," he mumbled.
Natasha's breath caught, heart swelling. "I love you too, sweet boy," she whispered, planting one last kiss to his forehead before slipping soundlessly from the room.
Peter slept peacefully through the night, warm and safe in the knowledge that his family would always be there to care for him, thermoregulation issues and all.