Only one, of course, would actually be telling the truth, and it fell to the contestants to decide whose story was most plausible.
As I recall, the very first object in the very first episode of the revival was this... thing... that looked more or less like a loop of barbed wire, with sharp spikes facing outward. One of the celebrities insisted that it was, in fact, a Mongoose Collar, and, after initial guffaws, spun an entertaining and entirely plausible tale about how, in India, the household mongoose would wear one of these to repel the deadly bite of the cobras they were kept to hunt.
The object turned out to be some kind of wool-comb for spinning, if memory serves, but for the rest of the episode, "mongoose collar" became a running gag, used (jokingly) to describe every other object presented in subsequent rounds.
Thus, a Mongoose Collar is:
- A gizmo, gadget, or thingamajig of indeterminate purpose or provenance; or
- An unlikely, implausible or blatantly incorrect answer chosen completely at random.