Most people have become accustomed to the outlandish collection of adaptations found in land animals and common ocean creatures. The elephant's trunk and the shape of the hammerhead shark's head, for example, barely raise eyebrows. We've simply seen too many of the creatures -- in pictures, on television, or in person -- to be very surprised by them.

However, many creatures that call the deep sea home live at such depths -- thousands of feet below the surface in some cases -- that they were unknown even to scientists just a few decades ago. Pair that newness with the fact that extreme conditions -- including crushing pressure, perpetual darkness, and unimaginable predators and competitors -- drive extreme adaptation, and you've got yourself a collection of creatures whose appearance will make your hair stand on end.