I've long had a memory of an episode of an animated show featuring Superman in which he was sent to a "mirror dimension." This dimension is mostly a featureless void, but scattered throughout it are mirrors, each occupying the same fixed position as a mirror on Earth. It's essentially an exact copy of the real world, except that everything except its mirrors has been removed. Superman can see through the mirrors into the real world, and be seen in turn, though he cannot break the mirrors to escape.
The main bit I remember is that Superman is flying from mirror to mirror, trying to get someone to help him, and when he reaches one particular mirror, we hear a woman shout "Eeek!" and Superman averts his eyes and says "Oh, sorry, ma'am!"
It might be that people on opposite sides of the mirrors heard each other's speech as reversed, so no easy communication was possible.
The Flash's enemy Mirror Master seems like the obvious candidate for the one who did this to Superman, but I don't specifically remember him being involved.
I used to think that this episode might have been from the 1988 Filmation TV series, but I watched it recently and didn't see anything like what I described. Now I'm starting to think I might have dreamed or imagined it entirely.
Does an episode like what I described actually exist?