Wrong planchet error 1968-D Kennedy half struck on a Jefferson nickel planchet. The error occurred when a nickel planchet was fed into a press striking Kennedy halves, resulting in a coin with the design of a half dollar but the planchet of a nickel. Although rare as a wrong planchet error, it is ever rarer with a date. Most are no-dates, and it's tough to find them with dates.
NGC MS-66 with blue/gold toning.