This bizarre deep-sea creature is called a barreleye fish, and it lives in the deep ocean.

According to an article at Mother Nature Network, the reason for its clear head is so its eyes (located inside its head) can look straight up to detect prey.

Those two spots above the mouth that look like eyes?

They're actually nostrils.

The eyes are those green globular domes inside the transparent head.

Those eyes can rotate within the socket so that the fish can look in multiple directions, which would be impossible if not for the transparent cranium.

I feel like I'm on Mars.