Men in Black Costumes
“You know what the difference is between you and me? I make this look good.” - Agent J
What do you know about fighting aliens? If the first thing that popped into your head was, “You need to wear a black suit, dark sunglasses and carry around a blinky-thing tool,” then you are definitely qualified to become one of the Men in Black. The blinky-thing tool is actually called a Neuralyzer, but that's just getting technical. The people whose memories you erase won't care what you call it, because they won't remember anyway.
So, once you get a Men in Black costume to give you the smart, cool look of an official agent you'll need to choose an agent name. These agents generally go by a letter of the alphabet so you don't need to go crazy, just pick your favorite letter. You'll be all set to hunt down rogue aliens and keep the unsuspecting people of Earth safe from intergalactic harm.