Protectors of the Plot
Continuum
A spin-off on the original series
Agents Twain and Jeanlily
Agent (er, sort of) Death
By Twain and Jeanlily
By an insane author, so don't ask.
What, you've never heard of the PPC?  I suppose I'll have to tell you then . . . friend.  You see, the PPC is an agency (if you can call it that) where agents go out and correct fan fiction worlds.  Let me give you an example: Agents Twain and Jeanlily work in the Department of Mary-sues.  Therefore, they go into an actual fanfiction story and kill the sue.  Death, on the other hand, works in the Department of Crossovers, and specializes in movies crosses with Sues.  Therefore, she must kill the Sues and correct the crossover (though, occationally, just killing the Sue gets rid of the whole problem.

Therefore, if you write bad fan fiction and you don't watch out . . . the PPC might come and get you.
There are many ways to kill a Sue -- it all matters what department you're in.  Twain and Jeanlily, now, they work in The Lord of the Rings, so they might use bow and arrows, poison, fire or a knife.
In the movie-verses Death works in, however, vampire stakes, guns, and even silver bullets work much better for Sues.  Of course, you don't need weapons in plain crossovers - but that hardly ever happens to her.  And she brins them anyway.