Rek'sai skin idea

I don't know if anyone else has already came up with this, I haven't just any posts, but I've been up for a long time and this just popped into my head.

Rek'sai's skin transforms her into a shark, a terror or the seas. When she goes underground, a wave(water) is left there. It's looks like a wave as it is breaking against the shore. When she is underground, her fin (like sharks) is up in the air! I can have some drawings done and posted within a week or so. Like I said, this idea hit me a few moments ago. Let me know what y'all think!