Oilicle

The oilicle has two tentacles that are modified to store oil. Like a shark's oily liver, the oily tentacles help keep the oilicle buoyant. The greater buoyancy reduces the amount of energy expended in movement, which is quite useful when there's not much food.

It lives 700 to 900 meters below the surface. The dim light of this ocean zone makes pigment less necessary. Consequently, the oilicle has less pigment, to the point its digestive system can be seen through its translucent skin.