A Bioluminescent Reskin or Two for Grimstone Layer

Hopefully, the glow squid will spawn in aquifers. But if not, or perhaps even if it does, a Bioluminescent reskin or two for the Grimstone layer could really add some flavor and variety to the mob pool and the new layer, and all without being too resource intensive. Even if there were no plans for this previously, I'd imagine that it would be relatively quick and easy to whip up a skeleton or spider skin that reuses whatever code causes the glow squid to have its unique effect. Perhaps glowing mobs could only spawn in certain underground biomes or only rarely, but maybe a weak luminescence effect could be used to make something analogous to a husk or drowned for caverns without ruining the atmosphere of these colossal pitch-black caverns. I suggest reskins instead of completely new mobs just for the sake of pragmatism and ease of implementation, but I don't think anyone would say 'no' to completely new mobs either.