Is this a human that turns into another creature?

*Some of the audience hums at the mention of transformation*
(KagomeShuko) Human that turns into another creature? NO but within their history, the AOTC has had a few methods of "changing" :)
(Bismarck) Science fiction? Hmm, there are many Sci-fi elements that come into this, so it is involved, yes.
I thought this could be simple but I forgot the AOTC has had so much variation over the years.

(Superman) Little green men? I like your thinking, but NO. (The AOTC has met little green men though).

Is transforming not necessarily transforming, but like hatching from an egg?

(KagomeShuko) AOTC = "Answer on the Card" or in other words : the answer you are looking for. As for the tiny hint about transforming: it is an everyday transformation that we are all capable of doing. The AOTC has a few nifty ways of doing it.
(Raak) Superhero? YES. *cue audience going wild with excitement*

(If it's not that, I *bet* it's either a bird or a plane!)

(Superman) Superman? (NO) NO.
(blamelewis) No birds or planes, at least not that I can see. *some audience tittering*

(Bismarck) Hulk? Incredibly NO.

(Superman) Baddie? NO

(Bismarck) Marvel? NO

This is bothering me. Everything I can think of that involves superhero persons changing doesn't involve little green men, and everything I can think of involving little green men doesn't involve changing. I'm stuck.

(Raak) Fast? YES. "Incredibly fast"? Possibly. The AOTC can move faster than us, some versions extremely fast. Not usually as fast as the previously mentioned Superman though.

(Bismarck) See note I made just above about changing to KagomeShuko. And "little green men" was only one or two story lines of many. Neither are particularly important in the grand scheme of things. Non-Marvel superhero : that does narrow things down a tad. :)