Beware of a wolf in sheep's clothing. Aesop
There is a very real danger that financial regulation will become a wolf in sheep's clothing. Henry Paulson
My food hero has to be Auguste Escoffier. And the villain? The man who's been most responsible for the death of food in my time is Ronald McDonald. He's always scared me, I think he's evil - he's a wolf in sheep's clothing. Him and the Hamburglar. Arthur Potts Dawson
Julian: What's black inside, white outside, and hot? Jenny: What? Julian: A wolf in sheep's clothing. Jenny: Is that what you are? Julian: Me? No, I'm a wolf in wolf's clothing. L.J. Smith
A wolf in sheep's clothing. Dutch Proverb
Rastafari purists also sometimes refer to such dreadlocked individuals as "wolves", as in "a wolf in sheep's clothing", especially when they are seen as trouble-makers who might potentially discredit or infiltrate Rastafari. Source: Internet