Growing up I used to have a really neat tropical fish aquarium and my fish of choice were the transluscent or ‘invisible’ fish.
Of course, I liked the idea you could see their insides,, but what I found charming was that even though they looked delicate but they were the fin nippers so you had to watch who you put into the tank with them.
That long ago hobby of mine has led me to be intrigued by anything in nature that looks like it was made of glass. For example I ran across a story about these flowers- the wonderfully named ” Skeleton Flowers ” They turn to ‘invisible’ when they get wet.

Diphylleia grayi, also known as the skeleton flower, has white petals that turn translucent with rain. When dry, they revert to white.
The ocean is full of invisible creatures, I could watch them for hours. To bad I can only see them on TV.

Translucent Comb Jelly Fish
I thought I would close with this video of a Glasswing Butterfly. I’ve always thought of butterflies as flying spiders. Nope. I have no idea why. But the idea of a flying spider that you can’t see? Come on, how awesome is that?