Thanks for the tip, Capcom.
If the mimics come back in future games, I hope they'll decide to give them some sort of visual identifier. It doesn't have to be obvious, but an easily overlooked tell like the lid of a chest moving slightly, or subtle discolouration from the maneater's drool staining the wood would make it feel less cheap to be caught by one, as well as making it feel more like player error when you are. Though that's assuming they'd be spread out over the entire game, rather than just one dungeon.