I had an idea, and I wanted to know if anything like it had ever been done before:
The character is mainly a street - leveler, with peak human stats, and an expert in many forms of armed and unarmed combat.
However, when his life or the lives of people he cares about (or a large amount of any innocent people) are in serious danger, he temporarily manifests superpowers. They are basically random each time, and can include things like super strength, super speed, durability, agility, flight, energy beams, matter manipulation/transmutation, resistance to extreme environments/poisons/diseases, and even low - level reality warping. However, the powers always go away once the threat/situation that triggered them is over.
Maybe I phrased that wrong, he doesn't get any power he needs to help himself in a situation, he gets a random power.
So for example if he was dying from poison, he might develop a new immune system/healing factor to negate it, but then again, he might develop X - ray vision instead, which would be pretty useless in that situation.
That power stinks. It doesn't stink becuase of you, it's just a crappy in my opinion; I mean, you could be dead because you gained a crappy power. Over all though, it could make a clever character. The power, however, wouldn't be tops on my list.
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The only thing thats with you your whole life is complete and utter darkness.
the problem with the random power is that he's not going to manifest a random power. he'll always manifest one that somehow gets him out of his situation and/or into another, because you can't have a comic's main character die "randomly" without having established himself. it's too conceptual to actually function in a comic sense, if you stick to the "random" aspect, because you can never truly be random while writing the story.
a better idea might be to have his problems solved indirectly or unconventionally. for example, if he was dying of poisoning, instead of manifesting a healing factor, he manifested several hundred pounds of excess fat [a la big bertha,] which dilutes the effects of the poison over his body to a large enough extent that he can continue doing whatever he's doing and get typical anti-venom treatment afterward. or things of that nature.
the same type of idea was brought up recently in cable and deadpool, though not capitalized on. [SPOILER - highlight to read]: deadpool had been shrunk down to a few inches in height due to rhino and some pym particles, and while infiltrating a hydra base, he came across a machine that could permanently rewrite genetic templates. and his initial solution was to demand a 'yao ming' template be used on him, which could seemingly reverse the process or whatever. but they just used pym particles instead. i thought it would've made an interesting way out of the situation.