Flaming Pumpkin

I support a melee weapon, but there are arguments that it would be either overpowered or underpowered. I think it should be both. I will explain. There is already a melee weapon in game and it fits for how I propose to balance it. The hunting knife. No katana, no lead pipe, no fire axe, just a basic hunting knife. First and most importantly the knife delivers a one-hit kill IF AND ONLY IF you are behind the target (be it zombie or player). If you need a example think TF2's spy. Secondly, it does little damage otherwise, with a long delay between swings/stabs either way. On a player it creates a bleeding effect. It makes no noise and after [insert number of uses here] it breaks. I propose this system as a risky method for silently clearing a area and a absolute last ditch chance for survival otherwise. The point isn't to make players more powerful but to give more options, for more styles of play.