He's awake!
The Avengers immediately leapt into action. All thoughts of the de-briefing were forgotten as each and every one of them raced to see what Tony's reaction to being a dog would be.
Bursting into the lab, they saw a strange thing. Tony was on the table playing with medical apparatus. Looking up and seeing the team, he barked once and looked down again, as if to say 'I'm busy'.
Clint started laughing loudly, which caused Tony to glance up again. "We came all the way here...and he doesn't even bat an eye at the transformation!" Clint giggled. "He's so cute too." Natasha groaned at her best friend's antics and looked curiously at Tony with sharp eyes.
Steve had the opposite reaction. He frowned and told Tony, "Don't play with that, you'll cut yourself." Tony, having looked back down after Clint's initial outburst, ignored him. "Stark!" Steve growled, before asking Bruce, "He can understand us, right?"
"Given that he's now trying to perform an experiment with dangerous chemicals and is doing everything in the correct procedure, I'd say it's very likely, yes." Bruce commented dryly. To Tony, he grinned and then turned serious, "Tony, your paws aren't that dexterous- stop trying to use a clamp." Tony, hearing that, whined and gave up on the experiment. He jumped down onto the floor and landed with a wobble, causing Clint to go off in giggles and exclamations of 'so cute!' and 'we should take care of hime, please, Nat, please!'
Tony steadied himself, and started heading for the door. Steve caught on, and reached for him, with a stern "Oh no, you don't!" Tony, displaying the agility of a Jack Russell Terrier, jumped nimbly to the side and barked at Steve, as if to say 'That all you got?' Steve frowned at him and began talking, "Stark, this isn't the time for childish gam-" Tony started sprinting for the door.
Skidding to a side, he sped down the corridor, his tongue hanging out as he panted. Steve looked at Tony's retreating figure, and yelled, "Stop!" Seeing that Tony ignored him, Steve groaned and gave chase. Clint, never one to miss out, also ran after Tony. As he left, he heard Bruce say, "Tony's really going to get it from Steve-" but was soon too far away to hear any more.
As Tony made his way down the corridor, he could hear thumping footsteps coming nearer and nearer. Seeing a door that was ajar, he rushed into the empty room and, seeing a bed, snuggled down deep into its covers. "No one can see me in here," thought Tony smugly. Tony was right as usual, of course. After a quick check in the room by Steve, he had concluded that Tony had run farther down the corridor and left, not knowing that Tony was right under the covers, quivering in excitement.
After five minutes, Clint finally puffed and panted his way to the room. Unlike Steve, Clint gave a thorough check of the room. Turning on the lights, Clint gave a soft whistle, and whispered, "Tony? It's me, Clint."
Hearing the familiar click of the light switch, Tony stiffened. Had Steve come back to check the room again? Then he heard a soft "Tony? It's me, Clint." and relaxed a fraction. He began weighing his options: Could Clint be trusted? He would find Tony eventually, but Tony never went down without a fight. Then again, Clint was his prank buddy and actually called him Tony, unlike Steve and Natasha. Thor didn't count, he was only part-time and called everyone formally, as was his culture.
After waiting a minute, Clint figured Tony-if he was there- wasn't going to come out, and started searching. Suddenly, he heard a bark behind him, and there Tony was, his tail wagging and a doggy-smirk on his face. Laughing to himself and shaking his head, Clint smirked back, saying, "Nicely done, hiding from Steve." His expression turned serious then, as he said, "You eventually have to go back though, so you better stop the game and we can go back to the lab, yeah? I can even sneak you some non-doggy food if you like."
Upon hearing that, Tony whimpered and put his head in his paws. It was then that Clint realised that Tony was actually very scared of the transformation and hid his fear behind jokes and games. Crouching down, Clint offered his hand, "Hey, it's fine! Brucie-Bear and I will take care of you, right? And Thor will find a way to change you back, so that we can prank people even better! Though," Clint lowered his voice conspiringly, "you would make an epic stealth weapon, using your cuteness to melt bad guys' hearts before i shoot 'em!" Miming shooting an arrow, he grinned as he watched Tony go back to his usual energetic state, wagging his tail in all his cute-doggy glory.
"Come on, let's head back to the lab now." Clint rose clumsily and opened the door. Trotting outside, Tony looked back once, as if saying 'You coming, or what?' Clint laughed as he followed Tony back to the lab.