Nice find. It's called a struck through grease error. https://www.error-ref.com/?s=grease They're rather common, but yours is more severe than most. It's a keeper for sure.
That’s not damaged, it’s a mint error. It was struck through grease and a lot of it. Nice find. Put in a flip and protect it.
It appears to be zinc. I doubt a struck through zinc cent is worth more than $1-$2 but what do I know? While the obverse and the digits appear to be struck through grease, the reverse appears to be the product of heat or chemicals. It may not be a keeper.