1968-S Jefferson nickel double-denomination struck over a Lincoln cent.
The coin has both the designs of a nickel and a cent, and is copper since it is struck on a Lincoln cent.
There are strong design details visible from the underlying cent, with much of the lettering and design visible on both sides.
This is a very scarce date and mint of this error type, and there aren't many 6c double-denominations from the 1960's at all.
PCGS MS-64 Red/Brown with a few small spots, but the coin is mostly red.