1984...help Again...wierd One

That's the result of a clashed die. It is very common on cents of that era. To the right you see evidence of Lincoln's beard and to the left you see the back of his coat. Remember that it is upside down due to the position of the dies as they clash.

You may, depending on what was done with the obverse die, see some details from the reverse of the coin on the obverse.

Yeah...clashes are often documented with overlays similar to yours.
Judging by the angle of Mr. Lincoln, it appears the dies are rotated somewhat.

The processthat resulted in that coin:

The obverse and reverse dies slam together without a planchet between them. The force of the strike imparts each of the designs onto the other die. When the die mints subsequent coins, the partial opposing designs are on the die, so they transfer to the coins. Pretty simple.

What some people look for (and they do actually occur) are way off-center clashes and double/triple/quadruple clashes. These occurrences are rather uncommon and are interesting to some collectors.

The only other clashes I can think of that have brought a lot of interest in the past are the clashes of different denominations together - how this happens I have no idea, but it has. There is an 1857 cent with a clash mark from a $20 gold obverse on its reverse. Those are highly sought after.

Very obvious clashes are also collectible to a certain degree. On Lincoln cents this would mainly be limited to clashes on the obverse of memorials where the columns are easily visible from the reverse, and clashes on the reverse where the entire head outline is visible as well as the date. The date would be half-hidden but sticking out of the top right part of the memorial building - upside down and backwards, of course.