A saying that can be added on to practically anything, or used on its own. It can be positive or negative, sarcastic or serious, can also have hidden meanings, which usually are not noticed due to the common usuage of the phrase. The term 'like a fox' first appeared on The Simpsons, when the Homer said "stupid like a fox."
"Damn, when did you get to be so smart?"
"Smart like a fox!"