Craziness.
The Barreleye fish, alternately and quite aptly called the spookfish, does not have any eyes on the outside of its head. In fact, they are entirely inside of the fish's head; the two external circles on its face which appear to be eyes are actually nostrils. How does the fish see then? Its head is a transparent dome through which light passes freely and its tubular eyes can see.
http://www.youtube.com/watch?v=8e0VuV6OHd4
Deep sea existence is wild.