1955 D penny Error?

To me that looks like a struck through error for certain. Something was struck into the coin coming between the die and the planchet when it was created. My first guess would be a capped die type error. So basically how this works is the previous coin sticks to the die instead of being ejected. A new planchet is inserted and the die strikes again. This coin appears to be the coin that was stuck to the die. Doing a little photoshop magic to figure out where the other coin struck give me a bit sorry.

These are areas in question...doing some research. I AI upscaled the image to something larger and am looking into it.

Normal Die Strike Visual

So this idea sort of at least measures correct. Meaning it was likely not done after the minting process but during with a coin or die of exactly the same size. So its likely a legit mint error if that makes sense.

The only real issue is that i dont know what letter number or shape on the reverse the of a penny made this indention shape. You know what i mean? That shape does not exist on either the obverse or reverse of a wheat penny.

No matter how i rotate this coin in photoshop using transparency layers I cant seem to create that character. While we have researched thousands of errors. This one is beyond us. Maybe a double struck capped die error, the coin was stuck to the die, rotated and struck another. We really dont know specifically. And if you cant find or make that shape using either the letters numbers and shapes or a combo therein then was it really made at the mint? If I were you I'd take it by a coin shop in person, maybe they can see something Im missing using just photos? Anyone else care to weigh in?