Here are the pics, and I see some glue, but on the rim of the hollowed out reverse, they left some verbage...
It's the Obverse shell of a spy coin. Any coin can be used. A magician's coin is usually shilled meaning a steel insert is added so it would stick to a magnet. The shilled shell would be placed over a smaller coin then using a magnet the shell is moved away revealing the hidden coin.
It looks like the nickel was ground down in a similar way to this 1859 cent. Before you get upset about "ruining an old coin," this was is listed as a Civil War token, and it was done when this cent was only a few years old. The CWT variety code is PA 360 A-Ido. It's a little scarce, but not impossible to find ... at least 20+ years ago. I sold a couple of these when I was dealer. I still have this one.