1983-P LMC Penny / Struck Through Dropped Filling / Dropped Letter "Y"

To simplify what I am saying, when you have a heavy clash on the obverse, people think the raised areas of the "jailhouse" clash is from the columns, it is not, they are the bays. So when you have a typical die clash, what is raised on the coin with be incuse from a clash. Hope that helps. What you have is a very nice, strong letter transfer from a clash though, not from a dropped filling.

You know, I have read the description on error-ref many times, and couldn't get my head around the clash being incuse. Guess I have been looking at clash marks all wrong. I have been interpreting what I see as clash marks, backwards.

Had to take time to really visualize the process, but,
I think it's FINALLY gotten through!

Thank You Everyone!
You just helped me unlearn my incorrect understanding, and replace it with the correct one!

Think of a die clash in two parts. The die clash itself strikes a raised, positive coin onto the opposing negative die. When that modified negative die strikes a coin, it makes a positive coin, but the additional positive features on the die strike negative features onto the coin.

I think of a die clash as holding the coin up to a mirror. Then everything you see that is raised in the mirror sucks down on the front coin face, from the center outwards, and from the fields first.

I am not sure what you are talking about. A die clash is exactly that, clashing of two dies, with no coin/planchet involved. The hammer die and anvil die hit each other with NO coin involved, that is how a clash is made, then the clashed dies, when they have a coin/planchet introduced, creates a coin with clashing on it.

I imagine others also look at a clash the way I had been, but I've got it in my head now! Thanks.
(The coin thing confused me at first, but after some sleep and rereading Brandmeister's explanation, I believe that I understand what he was saying: The clash creates a minted coin's feature [raised] on the opposing die, which in turn, creates the negative [incuse] feature on future minted coins.)
Bonus for me: By verbalizing Brandmeister's explanation (I really did that for my own benefit), it also popped into my brain how a counter clash is created.

Absolutely!
Sometimes being wrong can be very beneficial!

Yes. What you really see in the background of the struck coin is a partial reconstruction of the opposing die (not the opposing coin face).

It's an image seen through a mirror—but American coins make it loopy because we mint coins to be flipped top to bottom, so the dies are also 180 degrees rotated to each other when they clash.