1994 Penny Error?

The mark between the 9's is most likely a gas bubble. As far as the silver color, the coin was most likely plated in something, but I don't think nickel. I don't think that's magnetic.

I had never known about gas bubbles in pennies being a thing but that definitely makes sense. As far as the magnetism of nickel, yes nickel is a ferrous metal along with iron and cobalt and nickel plating things is easy to do at home with nickel sulfate hexahydrate and/or nickel chloride hexahydrate which you can just buy on the internet. it's a fun science experiment to try along with gold and copper plating things. I suggest copper plating all your nickels, dimes and quarters and nickel plating your pennies and confuse the crap out of an unsuspecting cashier.