Boom
(Concept based partly on this awesome drawing: post/24005340351/that-went-well)
Bruce Banner walked up the science lab in Stark Tower that he shared with Tony, thoroughly preoccupied with his own ruminations. As he logged into the console, he abruptly realized that there was something on the door. He adjusted his glasses and stared at it. It was a piece of white printer paper, taped to the door at a slightly off-kilter angle, featuring two stick figures scrawled in marker. One was clearly supposed to be Tony, due to the sharply angled goatee and blue circle on the chest. The other, Bruce supposed, was probably him. A scribble captioned the drawing: Super Secret Science Lab! Bruce stared at it incredulously. Was it a joke? Was there a hidden camera somewhere? He decided to ignore it and not give the prankster the satisfaction of a reaction. He yanked the door open, walked in and within a few minutes, completely forgot about it.
Several hours later, Bruce looked up to see Tony standing in the hallway, one hand holding the door slightly ajar, staring at the paper on the glass with his brow furrowed. He looked up and down the hallway, then turned and glanced across the wall behind him. Apparently not finding any cameras or people spying, he walked into the lab and began turning on his computers. Neither of them mentioned the new piece of art gracing the door.
It continued that way for weeks, months even. No one mentioned the new lab sign, although it was impossible to miss. New little doodles appeared occasionally. Test tubes and goggles. Beakers and a DNA strand. Really bad renditions of the equipment they used in the lab. A sun with smiley face and a rainbow and cloud over little purple and red flowers in a grass field, in the fashion of a seven year old girl. After a mission, a little Iron Man and a little Hulk showed up, holding hands. Bruce pursed his lips in annoyance over that one; Tony laughed heartily. Random stuff got added too, like the produce sticker off of banana or three stamps the day after stamp prices went up. 'Super secret science lab' was translated into Italian, Russian, Chinese, Pig Latin, and Quenya. Someone even taped several blueberries to the poster. But nobody ever mentioned the sign; not in the lab or at Headquarters or at home in the mansion.
One overcast spring day, Bruce and Tony sat in the lab, locked in disagreement. Tony wanted to titrate a variety of acids in a suspension of his newly created element to ferret out more possible uses for it. Bruce remained skeptical about the dangers of such an experiment.
"I still think we should take this slower, and wait for the computer models to finish…" Tony cut him off.
"Where is the fun in that?"
"Mixing new, unknown elements without proper gear or thorough research isn't my idea of fun. It's flirting with disaster."
"Well, I'm nothing if not a flirt." Tony grinned. "It's just a little science experiment, what could go wrong?" Bruce gave him a withering look. "Okay, bad choice of words. How about this: I've double checked my math, which is never wrong, and I'm confident that nothing catastrophic will happen." Bruce huffed and held his hands up in surrender.
"Your funeral," he muttered under his breath.
Ten minutes later the pair stood at one of the long counters wearing goggles and gloves. Tony handled the burette while Bruce took notes on a clipboard. Anyone walking by the lab would not have been able to help thinking that they looked like overgrown teenagers in a chemistry class.
"Fifty two drops," Tony announced as a ruby colored drop of liquid splashed into the beaker and dissolved away to an opaque nothingness. Bruce marked it down. They were both mildly surprised at the lack of a reaction so far, but they continued with the dogged patience of scientists. "Fifty three dr-"
BOOM!
The beaker and its contents exploded with frightening force. Tony had a brief glimpse of smoke and fire and super heated gas expanding rapidly, but the shock wave sent him and Bruce toppling over the other counter and they crashed loudly into the wall. By the time he opened his eyes again, various small fires were burning around the room and water was falling from the sprinklers in the ceiling. Bruce was coming to beside him. They stood up together and pulled the goggles off their blackened faces. Tony felt his features gingerly, hoping he hadn't singed off his goatee or eyebrows. He and Bruce looked at each others' reverse raccoon faces as they stood in the downpour from the ceiling. Tony grinned at Bruce's dumbstruck expression.
"That went well!"
The next day the sign on the lab had burn marks around the edges.