Maybe the fox and the scorpion, or
The fox saying it don't need the grapes.
http://en.wikipedia.org/wiki/The_Fox_and_the_Grapes#Sour_grapesOr the Chinese fox, that preys on the life-force of men, in order to achieve longevity. IE vampire.
Or possibly just using a word that has an attached positive mental label with many people. Since fox is a positive comment on a person.
Side Note: In the story where the fox swims across the river, thinking it could give the scorpion a ride. the traditional story ended with the scorpion in the story saying, he stung the fox, because that is what scorpions do. Now there is also an ending that talks of scorched earth, that says "it is better for both to die instead of my enemy to live" I find this interesting.
Here is a DU discussion with the original ending.
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=108x109877This ending has the moral that if you try to get power by making deals or by using corruption, that corruption will turn on you. No honor among thieves. and the idea that evil can not be used to do good.
http://www.angelfire.com/fl/EeirensFaerieTales/ScorpionandFox.htmlBut the new ending, top of Google, first listing when search for "fox and the scorpion", has the story with a different ending, making the scorpion some scorched earth thing, totally changing the meaning, but matching a current meme of threat from a certain class/group that claims power.
Edit: Everyone has some good and some evil in them, so just labeling anyone as either good or bad, I think is wrong and is not my intent, so for me, the evil of the scorpion does not represent a type of person but types of actions everyone sometimes do.