A Naval Criminal Investigative Service (NCIS) Polygraph Services Division "challenge coin" has recently appeared for sale on eBay, and AntiPolygraph.org has obtained a specimen:



One face depicts a skull with elongated canine teeth and an eye patch wearing a red headcloth and a black tricorne hat with the letters "DI" (deception indicated) inscribed on it, above crossed cutlasses, all against the background of stylized polygraph chart tracings. A spike on the electrodermal tracing pierces the skull's right eye socket from behind and returns through the nasal cavity. The challenge coin bears the inscription, "POLYGRAPHS DON'T LIE... PEOPLE DO." 

The pirate motif is a curious one for a law enforcement agency. The inscription is literally true. Polygraphs don't lie. They're inanimate objects. But they often produce erroneous results. And unlike their instruments, polygraph operators do lie—routinely—because, as explained in The Lie Behind the Lie Detector, polygraph procedure depends on the operator lying to and deceiving every person "tested."

The opposite side depicts the badge of an NCIS special agent and the words "NCIS POLYGRAPH SERVICES DIVISION."