Moths are scary. Giant moths are scarier. Giant sea moths - well, I'd probably faint if I saw one of these if I ever went diving, no matter how many times I was told that they're the gentlest creatures ever. It even scared me a bit to draw them. I'm sure all the manta rays of the world would laugh at me just like the one in the last panel is.
In the last but one panel, the ray is supposed to be stuck to the glass and waving and saying hello. But you can't hear it because the glass is really thick.