secret squirrel
n.β Β«All of us on the base knew that, like the detainees, we were likely to be under surveillance wherever we were. Watch what you’re saying, soldiers would joke, because the βsecret squirrelsβ are listening.Β» ββAn American in chains” by James Yee Times (London, England) Oct. 9, 2005. (source: Double-Tongued Dictionary)