Opinions About This Odd [1938-S] Lincoln Cent?

Seems odd to me:
If acid why not the whole coin?
Why the localized pin holes instead of across the whole surface?
It weighs 2.98 grams a bit low weight.
Nothing wrong with the edge that I can see.
Maybe just a bonkers coin that got into circulation?
I am documenting a small assortment of questioned coins and don't quite know what to make of this one.
So I call upon the forum for ideas and put those ideas on the printed album pages.

Throw a penny in a crucible and lightly hit it with an acetylene torch and I bet you could make a similar example.

But extreme heat was def involved, wether it was from fire or a chemical reaction.