What are the "rarest" BDs?

[Arkadin]

I mean amazon still has the Criterion dvd "The Small Back Room" in stock and it has been OOP for a while now.
nobody cares about paying $35 for it.
simple as that.
It is still OOP.
the meaning of OOP hasn't changed;
it means what it always has--the original studio/company/distributor is not making the product anymore for whatever the reason is.
the product has been deleted.
whether a store still has any copies has nothing to do with whether or not a cd, dvd, or bd is OOP or not.
the end.
EDIT: as far as the slipcover rarity game, that is a whole separate thing imo.
the OP simply asked about rarest blu-rays.
a rare first press bd with a sleeve could certainly be considered a rare bd--like Akira--but imo that's a little different than say Dracula with a sleeve because the sleeve is the only unique thing about the Dracula bd.
the Akira piece had a booklet as well as the slipbox that is not present in the subsequent pressings.
I mean is the Dracula bd WITH a slipsleeve a super rare bd?--sure.
but just Dracula by itself is obviously not.
these types of questions always come up when someone asks about rare bds.
edit: well the Robocop disc may be rare but it is worthless because it looks like total crap.
IF a rare bd market really develops in the coming years, imo the Led Zeppelin bd will be right there at the front because it was a released bd that got recalled and has an error on it.
the Robocop was never officially released from my understanding so that's a big difference.
I honestly don't ever see that Robocop being worth anything more than $15.
is it technically a rare bd?--I guess. sure.