Laser Shark

Massive, towering cyborg creatures created by a mad scientist from deep beneath the seas, Laser Sharks terrorize the shipping lanes of the world.

The sharks have to be cloned as they are endangered. They are ill tempered.

FlooBoo

FlooBoos are liquid ghosts, which exist under the water. They are generally the spirits of long departed sailors, fishermen, or pirates, who for one reason or another have chosen to stay behind for an eternity under the waves. Most of them have existed so long as to have forgotten all of their Earthly connections. They are generally friendly, and will guide ships through dangerous storms.

Karrakota

Karrakotas are overlarge squids. They are known to travel in schools and prey upon dolphins and small whales. They display signs of high intelligence, including elaborate social hierarchies and mating rituals. Old fishermen describe organized raids on shipping and coastal towns by the creatures, but most today consider these mere legends.

Sea Dragons

Dragons adapted to life in the open ocean. Like dolphins or whales, sea dragons are air breathing creatures and must periodically surface. Ancient adults are capable of remaining underwater for hours at a time. Sea Dragons are generally solitary creatures, and will have a lair in deep underwater caves with trapped air pockets.

Fishmonkey

Strange aquatic simians, Fishmonkeys live in the deep seas. They are notable for seemingly appearing overnight - one day from out of nowhere thousands of schools of the bizarre mutant just appeared out of nowhere, with no prior sightings or evidence in the fossil record. This has lead many to speculate they are extraterrestrial in origin.

Rahab

The Rahab is a sea demon mentioned in the book of Isaiah, and is also the guardian angel of Egypt. He was the (fallen) angel of rage and pride, and caused storms.

Tube Walker

Tube Walkers are land dwelling decedents of the deep sea worms which gather around hydrothermal vents. They have the ability to mimic characteristics of other animals which they consume.

They're pretty good with some lemon and tartar sauce.