Yup, it's just damage. Something struck or pressed against the obverse and a nickel was on the other side, leaving a partial mirrored impression of UNUM on your coin.
It's a 19xx copper plated zinc cent. Maybe someone had an aversion to the specific date?

Who knows...
In Memory of Crazyb0 12-26-1951 to 7-27-2020
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024