Jeff the Killer vs. Killer Fluttershy (not Murdershy)

I personally think that Fluttershy to be the better killer. She looks innocent and harmless and you wouldn't think of her as a killer until she slit your throat. Jeff is...well...Jeff. He looks like a killer. He carved a smile into his own face and burned off his eyelids for Luna's sake!

... Do you have any stories that feature this "killer" fluttershy?