So there was this one time I found a reasonably large bull ray sitting on the bottom of the river I dive in. They're not the biggest sea creature - I think this one from memory was about two and a half feet in diameter.
Of course their tail is something you have to keep an eye out for. Anyway, I was a bit bored that day so I got as close as I could to it and took a close up of its eye - for no other reason than I just wanted to see how close I could get before it swam away.
I got pretty close...