Fin Fang Foom
First Appearance: Strange Tales #89 (Oct. 1961)
All cards on the table, we Fin Fang Love Fin Fang Foom. He's a giant, alien, dragon who sometimes wears pants. What is not to love? But here's the thing, even though he's got a cool back story and an interesting design, when it comes to Iron Man, he's primarily the Mandarin's lackey. And while we're sure there will be some element of mysticism in Iron Man 3, we assume that, like the previous films, Disney is going to stick with science and gadgetry.
Fin Fang Foom is sort of like your buddy who wants to be a Hollywood actor but has a face for radio. It's better for him to stick at what he's good at. So we say, keep him to comics.