Welcome to the neighborhood! Can you remove it from the 2x2 and take new photos of both sides from directly overhead? Chris
I don't know what is on your coin but am 100% confident that SOMETHING was on your coin. That is just post mint damage. Not an error.
Environmental Damage and post mint damage..not an error Also.. Try to keep your thread title shorter.
It's possible that it was glued to something. Try soaking it in 100% acetone to see if you can remove it. Chris
The material on it has the appearance of scorched zinc, which I work with a lot lately, and appears to have left behind a circular design about the size of a penny. I'd say that a zinc penny was melted on it and left behind some material.
1942? That coin was in Indiana Jones pocket when they opened the Ark of the Covenent and everybody (including Jefferson) had their face melted. Seems pretty obvious to me, anyway.