You hit him with the falx, I'll untie his sandle!
It was used by the Thracians and Dacians to defend their lands against the Roman conquerers.
I can't think of any rpg that has includes this. I thought T&T had just about every weird weapon imaginable in it, but even it doesn't cover the falx. I'd treat it as an armor piercing sword, myself. And now I have an uncontrollable urge to use it in a game.