I have never came across this in my years of searching it looks like a crescent moon capped on Lincolns head. I have put it in acetone and here we are with this result.
the more I look at it it does resemble retained lamination. I showed it to a co worker who is not really in to collecting but still thinks old coins are cool and he said it looked like a eagle talon lol.
He didn't call it an interior cud, he said interior die break. Those do exist, retained and otherwise.