I would also like to be in the world of Ridley Scott's Aliens. I would be an expert on Xenomorphs, (don't look it up!), and I would die heroically to save my crewmates from the Xenomorph.
I would be another mutant from the company that made X-23. I would have four, instead of three, claws coming from my knuckles. (a little bit gross).
I would help X-23 and the surviving mutants on their journey to safety.
In DC comics
I would be Deathstroke's apprentice and wear a suit and mask similar to his. My archenemy is Robin and the Teen Titans.
In the Speedster Multiverse
I would be a sentient being composed of dark tachyon energy. I'm hired by the Speed Force itself to hunt down speedsters it deems unworthy or unnecessary to the time stream. My name is Paradox and I have a white suit similar to Flash's but has more armor on it. Instead of mainly lightning. The trail behind my speeding form would appear as more of me running. Each more transparent that the previous one as the trail goes back.
That's all for now...