Ceatures
The creatures are primarily going to consist of collections of post-consumer waste and trash that have taken on a life of their own and manifested into the shapes of primates. There may be other types shapes for their bodies, but the idea is that primates have made a mess of the world above sea level, and though they can not survive underwater, something has allowed their presence to antagonize the deep ocean through a seemingly evil telekinetic force.
Going with more of a monkey skeletal structure allows a tail to be used both as a weapon, like a whip or stinger, and can also help propel the trash automaton through the water, like an eel moves, or as a propeller.
I think it would also be interesting to have the primate-like force that has possessed these trash-beings to express some of the same problems and antics that humans and other apes do, like scratching their head because they are confused, or playing around, like standing on their hands as play, because they have no purpose until they come in contact with our protagonist, the anglerfish.
Generally, these trash creatures will be clumsy, but that doesn't mean that they are not extremely dangerous. They may also appear as amorphous piles before taking their shape, and may even transform into different shapes.
