This 1999 Lincoln cent is a (2) coin bonded pair, with both coins bonded together. One coin was struck while overlapping the other coin, and when it was struck, it bonded to the other coin. A rare and popular error type.
NGC MS-67 Red (the coin is loose in the holder because the prongs in the holder weren't able to hold the coin in place.) Note: there are white, cloudy scuffs on the holder which are not on the coin.