There is no possible way I was the only one thinking WHERE ARE YOU DOCTOR! during the Avengers. This was my little nonsensical idea that was born. I'm a silly person. (And this is tenth doctor, long live the lovely David Tennant)

Tony Stark attempted blasting through to the machine controlling the portal, only to have the impact thrown back at him.

"The barrier is pure energy. It's unbreachable," resonated Jarvis's cool voice within Stark's (not iron) suit.

"Yeah I got that," Tony replied. His eyes caught something, and he turned to view the Loki's smug-faced figure. "Plan B."

Jarvis had began to speak again, presumably about some technical difficulty, when a shout interrupted him. Tony looked to the rooftop, where a figure that he could have sworn wasn't there before stood.

"Hey! What did you hit that beautiful bit of machinery with?" The man hollered. He had an accent, British, and wore a long brown suit. How he appeared on the roof, Tony had no idea.

"Why do you want to know?" was Tony's answer after swerving closer. A bit coldly put, but who the heck was this guy?

"You need to shut it down, and I think I can help with that," the man said, grinning ear to ear.

Tony frowned. "It's got a barrier of pure energy. If I can't get through it, no one can."

The man only grinned wider. "We'll see about that, won't we, huh?"

He whipped out a small metallic device from his jacket, and pointed it at the machine. First the energy shield slowly flickered, before altogether vanishing, and then came the sounds of the machine dying. The man gave his device a flip before pocketing it, and turned to Tony.

"There ya go," he said with a wink.

Tony flew himself down to the roof, walking towards the strange man. "What's you're name?"

There was the smile again. "The Doctor."

Tony halted in front of him, and programmed his mask up. "No, really, cause you just saved me a colossal amount of time and effort, so I'm thinking of making a statue of you. Gotta have the name for the the little plaque at the bottom, you know. I'm not kidding. I'm really not."

"Yeah it is, just the Doctor. Promise."

"Ok, now what was that, that you used to, ehm, kill the portal machine?"

"Aw, this?" The Doctor took out the small device again, handing it to Tony.

"Yeah, yeah, this little cutie," Tony said, examining it.

"Sonic screwdriver."

"You know, I have never heard of that. Almost embarrassing, considering my industry."

"Nah, you wouldn't have them here."

"Well I know what to put on my Christmas list. I'm sorry, did I introduce myself?" Tony handed back the screwdriver (how on Earth was it a screwdriver? Since when did sonic simply destroy advanced technology? Questions later, business first...).

"No, you didn't, but that's quite all right. You're Tony Stark, you're Iron Man, and you're gonna do great things Mr. Stark, things greater than you've already done," The Doctor was grinning again, and suddenly wringing Tony's hand as he spoke. "Cause you're brilliant, really brilliant, not quite as brilliant as me, but brilliant."

With not much else to reply with, Tony nodded. "Thanks. Well now that I know who you are and you know how I am, there's someone that I think you, Doctor, should have the honor of breaking the news to that the big unfriendly portal machine is dead to. Come on, I'll give you a lift."

Sooooooo, Doctor meets Loki? No? Yes?