The extreme bottom of the oceans are the most mysterious places. People have not gone that far yet to identify what really is inside the bottom of the ocean. 

I have seen an interesting video from the planet Earth series which describes about living beings that live deep inside the ocean. These living beings are usually blind and has no visibility to see anything. One main reason for this could be because they have no necessity to see anything as everything out there will be completely dark. They find their prey and food in complete darkness. 

As the creatures live in complete darkness, they don't even have any color in their body except white color. They don't get to see any light or brightness at all. There is no possibility that sun's light can reach that level of depth. The team that shot the picture of these creatures used an infrared cameras to capture their movement and lifestyle. I don't remember more details about them. You can Google and find information or watch the documentary. 

Some of these creatures deep inside the ocean even have transparent bodies. They are bioluminescent.