The Furious Fangtooth Fish. Found only deep within the bowels of the world’s oceans, the Fangtooth Fish is surprisingly harmless. So harmless, in fact, that their scientific name comes from Greek anoplo meaning “unarmed” and gaster meaning “stomach”.
Sea Butterfly photographed by Ingo Arndt. Tiny marine shelless snails known as sea butterflies take many forms, including heart-shaped, such as this species in Antarctica's Weddell Sea. via National Geographic
The aptly named Ping-pong tree sponge (Chondrocladia lampadiglobus) is a carnivorous sponge. Those ping-pong ball looking things are covered in tiny spicules which the sponge uses to catch tiny crustaceans.
A deep-sea chimaera—a cartilaginous fish related to sharks—seen by the Little Hercules in the Sulawesi Sea. Its snout is covered with tiny pores capable of detecting perturbations in electrical fields generated by living organisms. Image courtesy of NOAA