One common trope of RPGs are the "bane weapons". Say, there's this axe that deals more damage to elves, or an arrow that's better at killing dragons. I won't go into detail why in a world, where one item can only have one enchantment, is this a bad idea, so I'll just quote one of my OCs:
Oh, a weapon that's tailored to kill those "pointy-eared bastards", sure it was of much use when the zombies were gnawing away your legs. You must have looked like Rajk László when he saw the ones putting the rope around his neck were of the very same organization he helped to build. Rest in Pepperoni, you racist piece of (beep).
-A protagonist (who happens to be an elf) reviewing the Whoostrad (which is totally not a copyright-free Wuuthrad)
Anyway, the key problem is that a dragon's armor isn't made of dragon, it's made of an organic short-fiber composite, a material that isn't always associated with a dragon. And similarly, a pissed of elf's plate armor is made of plate armor and not elf; so the weapon that only deals extra damage against elves, even though it has to bust through a distinctively not-elf-but-steel plate armor; makes zero sense, or even less.
Yet the Whoostrad does just that, extra damage against elves. On top of that, everything (even the naruto-running titan zombies) have a scientific (though bizarre) explanation here. So, how can this bane weapon be explained with science?