ooops---that be a 2010-P. found in a box a few weeks back. error-ref. makes note of this condition, either missing layer or faulty annealing causing molecular anomaly between copper & clad layers
guess it beats 2499 skunk dimes
What is the thickness of said coin? It simply looks to me as if it was either tumbled with copper coins or had some chemical reaction. The design appears too crisp to be otherwise.