What would you give for a working lightsaber? Or, barring that, a pulse rifle from Aliens?
If we could make fictional weapons real, there's no limit to the ass we could kick. That's because writers and prop departments are usually pretty good at coming up with weapons too badass to exist. Usually.
Sometimes, though, they get so involved in making something that looks cool on the screen that they come up with a weapon that, in reality, would be more dangerous to the guy using it. For instance...
Why It Could Be Cool:
Because he's the goddamned Batman.
Why It Absolutely Is Not Cool:
We all know Batman loves to maintain a consistent theme. And we're fine with that. We don't mind that he calls his car the Batmobile, or his hideout the Batcave, or his computer the Batputer, because it doesn't affect his crime fighting. If he wants to have a cool bat screensaver or a bat-shaped birthday cake, whatever, as long as it works.
It was at the invention of the batarang that somebody should have intervened and told Bruce to spend less time worrying about every single accessory fitting the theme. Making your deadly boomerang thing bat-shaped makes it hard to store, hard to throw and, in reality, would be next to impossible to catch without severing three of your own fingers.
Look, Batman, the bad guys aren't going to care what your weapon looks like once it's lodged in their neck. Don't worry about it, you look fine. Quit primping, get out there and stop some goddamn criminals.