[Ichneumon]

A flying ballon.

That'd be my guess. The first (recorded) *manned* hot air balloon was in France in 1783, but people must have been fiddling with smaller toy balloons long before that.

And the ornate patterns on the Mongolfier's balloon do bear a resemblance to the ones on the "thing" on the coin:

[Popman]

Funny how the article leaves the "balloon" possibility out of the article.

That was my "first" impression. UFO fell way down on the list.

Do I detect a underlying "snake oil" salesman trying to up the price of the "UFO" coin.

Art Bell would be proud.