Translucency or Transparency as an Option for for Flesh on a Being

Sometimes people go fishing for deep sea fish and pull them up, and it looks like they've got some giant tongue sticking out of their mouth. That's actually their guts being inverted by thechange in pressure, because they've got like a swim bladder. And so this is wondrous when you start thinking about, well, what does it mean when you have translucency or transparency as an option for for flesh on a being, imagined or otherwise?