Well this was a fun one to write. In this case, my own little prompt was lifted off one of my other story's end AN, where I joked that when the Hulk saves Tony, he's thinking "NO! SCIENCE BUDDY!"

So yes, the prompt was 'Science Buddy.'

Also, I definitely did the spontaneous focus switch again. Like, twice. Sorry.

It had taken Tony quite some time to talk Bruce into the experiment. Honestly, Bruce still wasn't quite sold on the idea, but Tony could be very persuasive (irritating, incessant, and badgering were probably better words).

Since the attack on New York, Bruce had been living in Stark Tower. His alter-ego had gotten some good press as an Avenger, and combined with the personal protection of everyone's favorite Billionaire/Superhero, for the first time in too long, Bruce didn't have to worry about the US Army trying to get him– or worse, set off the other guy.

He didn't remember much of the fight, but Tony regaled him in details as the two of them worked endless hours in Tony's labs together. (Bruce found himself amazed at the stories, but also at Tony himself– Who else could actually find a way to brag about almost dying! 'So then I got myself under the missile, and flew it right into the portal. Yeah, I guess it was amazing and brave and heroic. I almost didn't make it back.' Only Tony… Bruce thought.)

One day (or possible late one night, as the two of them often completely lost track of time in the R&D labs), Tony, completely out of the blue, looks up from the piece of Iron Man's leg he was tweaking and says, "I can't believe they think I don't play well with others."

Bruce knew immediately who 'they' were– he had read the personality profiles, too. "Tony, why do you even care what your file at SHIELD says?"

"I don't," he insisted. "It just seems like a double standard."

Bruce raised an eyebrow.

"Well no offense, but if anybody needs a crash course in teamwork, it's Mr. Repressed Rage Monster," Tony explained.

Surprisingly, Bruce wasn't offended. He used to always have some sort of reaction to people talking about the other guy. Usually, it made him angry (though not too angry) that people treated him so differently, so alien, for something he didn't want, didn't like, and fought to repress. People were scared of Bruce Banner, even when he wasn't the Hulk, and he hated it. But Tony was different. Tony wasn't afraid of the other guy and he certainly wasn't afraid of Bruce. Hell, Tony even joked about the monster Bruce kept bottled up, teased him about it. He jokingly (usually jokingly) tried to egg out the monster, just because he found it amusing to, and though Bruce knew that he shouldn't be okay with that, something about the way Tony talked about the monster (almost like that awkward friend that makes you look stupid, but you love and stand up for anyway), made Bruce feel… accepted. Tony never implied that the other guy was a bad thing. He never looked afraid when Bruce told him about the glimpses and moments he could remember from being the Hulk. He never gave Bruce one of those angry, hateful glances he'd grown accustomed to in the outside world. It was nice, to say the least.

"Seriously, though. You know you punched Thor? Right after fighting side by side with him. You guys took out a giant flying caterpillar-whale together, and then just WHAM! I mean, at least the first few times to punched Thor, it's because you were actually fighting each other. Though I have to admit, I understand the urge to hit the guy, and I sort of wish I had it on video…"

Bruce laughed, something he was still getting used to after years of being without it. "I'll make sure to record it next time I get in a fight with the God of Thunder."

"Good. Until then, I'm just going to have to watch on repeat you smashing around Loki. That I do have on video, and God, does it make me love security cameras!"

Bruce laughed again, harder this time. He'd seen the footage too, and he had to admit, it was pretty freaking funny.

"But Gods aside. I really think you need more team building work than I do."

"I'll get right on that," Bruce joked.

But Tony smiled. "I was hoping you would say that."

Bruce looked at Tony warily, but he just kept grinning, waiting for Bruce to catch his drift.

"Oh no," Bruce said. "No no no. No way. I won't do it."

So yes, it had taken Tony quite some time to talk Bruce into the experiment, but here they were, upstate New York, surrounded by trees and fresh air and no people for miles.

"This is such a bad idea," Bruce complained as they got out of Tony's car.

"It's a brilliant idea," Tony corrected. "Of course it is; I came up with it. I'm a genius, haven't you heard?"

But all of Tony's joking couldn't make the sick feeling go away. Bruce wanted to hurl. He was about to intentionally let out the other guy, and he was going to do it standing feet away from Tony, the closest friend he'd had in years, to see if the Hulk would try to kill him or not.

Tony saw the look on Bruce's face. He put a hand on his shoulder, "Even if you do try, I'll be fine." He held up his briefcase by means of explanation. Tony would be wearing the Mark IV for this experiment.

"Tony…" Bruce started to argue.

"Nope. You're not backing out. No ifs ands or buts. Just keep thinking to yourself 'Tony Stark, friend,'" he said in a growling impression of the Hulk. Bruce smiled, so Tony continued, "'Tony Stark, not food. Tony Stark, science buddy.'"

Bruce laughed. "Science buddy? Really?" he rolled his eyes. But Tony's joking managed to reassure him a little. All he needed to do was remember that Tony was a friend. It worked with Betty, hadn't it? He still dreaded it, though. "Let's get this over with."

They didn't walk too far into the woods, just far enough that Tony didn't have to worry about his car (of all the things Tony should be worried about, he picked his car). Tony then put on the armor, and through the helmet said, "Whenever you're ready."

Bruce stood silent for a while, facing away from Tony. He was taking deep breaths, and for a moment, Tony thought Bruce was going to back out of the plan. Finally, though, it happened. Bruce's entire body tensed, and he grew. His skin turned green and his muscles budged out, ripping through most of his clothing. Within seconds, the Hulk towered over Tony, who suddenly felt small in his armor. He looked mad, as the Hulk always did, his mouth set in a frown and his chest heaving as air panted out through his nostrils. He saw Iron Man, only a few steps away, and his eyes tightened.

Maybe this wasn't such a good idea after all, Tony thought. But it was too late for second-guessing now. The Hulk was walking towards Tony with slow, deliberate steps. Slow and deliberate didn't stop them from pounding against the ground, though.

Tony didn't move. He didn't breathe. This was what he signed up for. Team building, here I come!

The Hulk bent over to see Iron Man better, looking right into his glowing blue eyes. "Stark," he said, in a deep, animalistic voice.

Tony was stunned for a second, but regained his composure and said, "Hey buddy," in the most nonchalant voice he could manage.

The Hulk was so close, Tony swore he could almost feel the monster's breath running down his neck, even through the armor, and he shivered.

"Science buddy," the Hulk said.

Holy Shit, that worked, Tony thought. He laughed, which seemed to startle the Hulk, but not offend him. "Science buddy: that's me," he agreed.

"Friend," the Hulk added.

"Science buddy and friend. Looks like you are in there, Brucey."

The Hulk glared for a moment, seemingly in distaste of the nickname (or maybe just in distaste of Tony altogether). Then he looked away, and slowly, began to shrink. The green drained out of him, taking the muscle with it, and as he returned to normal, he fell to his knees and put his head in his hands.

Bruce seemed more scared now than he had before the exercise, he looked around frantically until he saw Tony, who retracted his mask to smile.

"Well that was fast," he commented, obviously pleased with the experiment.

"What… What happened?" Bruce asked.

Tony's grin widened. His answer was amused and smug. "You called me science buddy."

I don't think Tony is ever going to let Bruce live that one down.

Also, for something quick, cute and funny, type /watch?v=KCOHAvIcnWA after Youtube. It's titled Drunk Science, and it stars Tony and Bruce, and it's hilarious!