'Wait, no, don't try to distract him with weapons! Just give him a doggie treat or something!'
'Where the fuck would I get a doggie treat in my lab? Here, he likes weapons, let's —'
'Don't throw a high-power rifle, oh my god, Tony, what is wrong with you?'
'What, it's not like it'll explode, I know things about — what. What is she doing.'
'Oh my god, no, nonono, please god strike me blind I can't be watching this.'
Steve stops with his hand raised to knock on the door, and considers just leaving. Usually, when conversations between Bruce and Tony take this sort of heated tone, something has gone terribly wrong and the fabric of the universe might very well be in peril. Steve turns on his heel to get gone before anyone notices him loitering in front of the lab, but then there is a high-pitched noise that sounds suspiciously like 'OhmygodohmygodSteve!'.
'Oh, no fucking way,' Tony yells from the lab.
The doors fly open and before Steve can work up any sort of reaction, Bucky is tackling him to the floor in a massive bear hug. All air rushes out of Steve's lungs and god, okay, Bucky is heavy, and also not usually all that handsy, but Steve's protests die in his mouth as Bucky licks a long, wet stripe across his cheek.
'Hi,' he says, sounding giddy and a little drunk, 'Steve, hi, missed ya, where do you go when you're not here, you're my favourite.'
'Um,' says Steve, which is about all he has, because then Bucky kisses him on the mouth, grinning and sloppy, and Steve nearly dies of a heart attack.
'You're my favourite,' Bucky repeats, pressing his nose to Steve's cheek, 'always, you're always, let's go for a walk, let's go running, it'll be so great, you're my favourite.' He lifts his head, and looks Steve straight in the eye, and his expression suddenly goes a little panicked. 'You like me, right, you like me?'
'Of course I like you.' Steve doesn't even think about it. 'You're my favourite, too.' Which maybe isn't the best choice of words, even if it's true, because Bucky smiles, sunny and unguarded and completely ecstatic, and kisses Steve again. Steve actually thinks about just saying to hell with it and kissing him back, even though Bucky is clearly drunk, but the choice is taken out of his hands when Bucky sighs in content and presses his face to Steve's neck and sort of curls up on top of him.
After a beat, 'I'd like to know what's going on,' Steve says loudly. 'Now.'
Bruce's head pops up in the doorway. 'Transfer of consciousness,' he says. 'Uh, basically, we were experimenting and Bucky and Clint and Natasha were bored after a mission —'
There's a loud hiss from the lab, and Tony screams. Bucky lifts his head, scowling, and lets out a growl. And then drops back down to — oh, god, is this a cuddle? Steve pats him awkwardly on the back and tries not to blush.
'Bucky has the personality of a dog,' Bruce finishes, looking pained.
It's just a testament to how strange Steve's life is that he just thinks, right, that explains a lot.
'And Clint and Natasha?'
Bruce clears his throat. 'Pigeon and cat, respectively.'
'Oh,' Steve says. He closes his eyes for just a moment, but lying on the floor with Bucky clutching him like his favourite chew toy won't help anybody in this mess, so Steve pokes Bucky a little and says, 'Hey, buddy. I have to get up.'
If anything, Bucky makes himself more comfortable.
Steve tries his command voice: 'Bucky, off.'
It works. Bucky jumps like he'd been burned, landing in a mess on his back, and stares at Steve. He shifts, tilting his head up, and doesn't break eye contact. He…oh. He bares his throat. Steve feels colour rushing to his face. He's pretty sure this isn't their regular dynamic, and Bucky sprawled on the floor like that and looking Steve straight in the eye, well, it does things to Steve's lizard brain.
'He thinks you're the alpha, that's very interesting,' says Bruce.
'No,' says Steve. 'It isn't. C'mon, Buck, let's go inside. Okay?'
Bucky nods. He gets to his feet in one fluid movement, and practically presses himself to Steve's side. 'You smell nice,' he says.
There really isn't anything Steve can say to that, so he just throws his arm over Bucky's shoulder and tries not to look too happy when Bucky just sort of clings to him. When he turns to Bruce, Bruce is carefully looking elsewhere.
Inside the lab the whole licking-kissing-snuggling is actually a relief, because at least the animal they switched Bucky's brain with is sociable and obedient.
'Cap,' Tony says, looking harried and terrified. 'Oh, thank god you're here, I can't take this any more, she's like something straight out of a cat video on Youtube.' He points at Natasha, who sits cross-legged on top of his desk, and watches the proceedings from under her lashes. From time to time, she licks her hand. When they come into view, her eyes zero in on Bucky and she hisses.
Bucky makes a move like he wants to go after her, face all lit up, but Steve holds him in place.
Bucky's shoulders slump. It breaks Steve's heart, but he stays firm: Bucky has no impulse control, he can't just start chasing Natasha around a table. He'll thank Steve later.
'Bored now,' Natasha declares loftily. She moves into a crouch and jumps onto a tall shelf full of robot parts. It wobbles, and Tony makes a sound like he's dying on the inside, but then the shelf stabilises and Natasha lets herself stretch out on top of it, purring. She hops onto her back, one leg hanging over the edge. 'Yes,' she says slowly, 'good. This is acceptable.'
Steve keeps watching her for another moment, then turns to Tony and Bruce. 'She looks pretty harmless.'
'Have you seen how cat hygiene works?' Tony demands, pointing an accusing finger at Natasha. She purrs again.
Steve blinks. 'What? I don't —' He stops. Cat hygiene? Isn't that when a cat — 'No way,' Steve says, boggling.
'Yes way,' says Bruce. He looks like he kind of wants to fan himself. 'She's bendier than any of us suspected.'
Tony nods gravely. 'There is nothing in the world I'd like to unsee more than the past five minutes of my life.'
Bucky headbutts Steve in the jaw. 'Hey, you wanna go for a walk? Let's go for a walk, let's run, let's go for a run? You could throw me stuff?'
'When do you plan to have this fixed?' Steve asks. He half-heartedly scratches Bucky behind the ear, just to see if that'll distract him. It not only works, it works too well: Bucky lets out an ecstatic moan and slumps, boneless, against Steve. He mumbles something incoherent and presses his face into the crook of Steve's neck and really just kind of climbs him like a tree.
Tony and Bruce stare, then force themselves to stop.
'Uh,' says Tony. 'I'd say within the week.'
'Week,' Steve repeats, a little light-headed. He wants to rant at them, because they absolutely deserve it, but then Clint's head appears, upside down, from a vent in the ceiling.
'Mine?' he barks, eyes fixed on Steve, then Tony, then Bruce. 'Mine? Mine?'
'A challenge,' Natasha says, 'yes, good.' She jumps down from the shelf and stretches in a way that looks anatomically impossible, then positions herself directly below Clint. She looks like she's readying herself for a leap. 'Perfect. I will tear your flesh and snap your bones. I am the greatest hunter.'
'Can we hunt?' Bucky wants to know, and Steve grabs both his arms to keep him from jumping up and down. 'Hunting time! Yep, yep, yep. Point me?'
'Bucky, sit,' Steve snaps, and Bucky drops down, eyes wide. 'Good. Stay.'
'Staying,' Bucky says, nodding. 'I'm good. I'm not moving.'
She turns to Steve, eyeing him suspiciously. For a terrifying second Steve wonders what he's supposed to do if she decides to rub up against him or something, but apparently she doesn't like him enough for that; she just fixes him with a stare and waits. Steve looks around the lab, bordering on frantic — and there it is, Bruce's fluffy sweater, the one Thor knitted for him. Steve unceremoniously rips off one sleeve, ignoring Bruce's pained gasp, and wraps it into a ball.
'String,' he commands, and while Tony looks around in confusion, Bucky scrambles to his feet and makes a beeline for one of the work benches. He comes back with a long piece of string, grinning like he won the lottery.
'Thanks,' Steve says, then adds for effect: 'Good. Sit?' Bucky sits, and butts his head against Steve's thigh. Steve ruffles his hair, then gets to work.
His masterpiece is pretty shoddy, but when he lets the fluffy ball hang swinging from the string, Natasha's eyes go narrow and she smiles, wide and dangerous.
'I accept this new challenge,' she says, and throws herself bodily in Steve's direction.
With a yelp, Steve throws the ball; Natasha runs after it, right into where the lab is most crowded, bits of machinery flying everywhere. This time, it's Tony who makes a mournful noise.
Steve scowls at him and Bruce, his best and often-employed I am disappointed in you, son; you disappoint me look in full force. 'And you. Fix this, or I swear to god I will lock you in here with them. Understood?'
'Okay,' says Steve. 'Fine. Okay. Bucky?'
Bucky perks up, grinning.
'Let's go for a run.'