NGC 2013 silver eagle with a major finned rim from about 4 o'clock to 10 o'clock on the obverse. The coin has a massive, high area of finning, which is where the metal protrudes upwards.
It occurred when the planchet was struck maybe 2-3% off-center, and was forced downwards into the collar die, but with the 2-3% off-center portion being "jammed upwards" against the edge of the collar. NGC described it as a horizontally misaligned die (we think it's better termed a finned rim.)
Very scarce like this, and one of the nicest examples we've seen in terms of eye-appeal of the actual error.