snake-in-the-woodpile 

(Noun) A trouble-making, untrustworthy person who often places themselves near to others in the hopes acquiring or overhearing information that they can distort and falsify.

Nickki whispered to Robin, "I need to tell you something, but that snake-in-the-woodpile Brandy is trying to eavesdrop on us. Let's go outside so that the cunt can't hear us".

snake-in-the-woodpile by Nikki Stixx May 7, 2019

Snake in the woodpile 

A person who slithers around causing trouble for others while keeping thier hands clean in a group. Example a co-worker using manipulation to get another person to tell on a 3rd.

Watch your back, he is the snake in the woodpile.

Snake in the woodpile by Reno' Bellerin May 10, 2018