This is the only time I have said this, but it would help to clean the coin in that area, that is your only chance of knowing 100%. My guess is that it is just a corroded cent, when they get all corroded they start to look like a WAM
Yes - at mostly zinc with a thin copper coating you never know what you have - especially a metal detector find!! It doesn't take much for just a mild acid (even like vinegar) to eat through that crappy thin copper coating to just get gone exposing the even more erodable zinc planchet!! I bet you didn't know erodable was a word