Biollante

Biollante is a monster in the Godzilla series of movies. Biollante was created by splicing human, rose and Godzilla's own DNA.

Vampire Worms

Large, parasitic worms which inhabit deep swamps and wetlands. Vampire worms have been known to swam over prey and quickly drain them of fluids. Like the creatures after which they are named they stay out of sunlight, and have been observed burying themselves into deep mud during the daylight hours.

Glums

Glurms are small, inch-long worms known for their devastating effects upon ecosystems. Glurms use a highly acidic digestive juices to rapidly consume plant life. They have been known to destroy large forested areas in a matter of weeks.

Pohlosephite

The Pohlosephites are a race of giant, squid-like entities which come from deep space. The creatures are actually quite intelligent, and communicate through a complicated series of touch, sign language, and bio-luminescent signals.

Clodds

Clodds are living rock people, who usually take on the form of short, squat boulders or stones. They prefer to roll along the ground when traveling long distances.

Oddrah the Oddball

Oddrah was a highschool chemistry teacher who was caught within a strange explosion during an afternoon lesson. The exotic chemicals mutated her body into a bizarre, grotesque form, however a result of the mutation, Oddrah's IQ has increased five thousand percent. She has since gone on to win several nobel prizes for advanced theoretical physics, mathematics, and medicine.

"Hairy" Type aliens

In the early days of the UFO phenomenon, hairy dwarf like creatures were often reported, especially in South America. The creatures are usually described around 3 feet tall, covered in long hair, with glowing eyes. Unlike other alien types (such as the Greys) they act more animalistic in nature, often relying upon brute force. In one such instance,  December 1954 in Venezuela, four such creatures were seen stepping out of a hovering craft, and attempted to forcibly abduct two young men who were out hunting. One of the hunters hit an attacking dwarf with the butt of his rifle, only to have it splinter into pieces, as if it had struck a solid rock.

Earcerci

Earcerci are bipedal aliens which are descended from deep soil burrowing insects. They have short limbs, a flexible exoskeleton which covers their body in rib-like structures, and walk with a bow-legged gait. Their brains are highly developed, and possess a unique five-lobed structure. Unlike most insectoid sentients, the Earcerci are individuals, and do not share a hive-mind. Earcerci society however still maintains many cultural holdovers from a hive-mentality, including a rigid caste system.

QuadKrab

QuadKrabs are large, multi-limbed entities descended from deep water crabs. They live in large communities seated in the walls of deep sea canyons and crevacies.

The Loch Ness Monster

The Loch Ness Monster is a famous cryptid which supposedly lives beneath the waves in Loch Ness, in Scotland. Sightings of the creature go back hundreds of years, but it wasn't until the infamous "Surgeon's photo" in 1933 (later proved to be fake) that the creature became known world wide. There are many theories of what the beast could be, the most popular being a relic plesiosaur population from millions of years ago.

I imagine a highly specialized Plesiosaur adapted to living in Loch Ness, mutated through centuries of inbreeding. The large, sensitive eye helps it see through the dark, peat filled water and keeps the creature away from the surface and blinding sunlight. The tentacle like structures on it's chin help it root through the mud along the bottom for hidden prey. The extended growths along it's "ears" are a new type of sensory organ which allows the monster to detect changing water currents and thus approaching fish.

And why a cyclops? Because it looks cool.

GibberWurm

The GibberWurm was a lowly sanitation worker who was contaminated by illegally dumped radioactive waste. The radiation bonded his DNA with a tapeworm parasite which was currently residing in his intestines, transforming him into a strange tapeworm-mutant hybrid.

Mamenako

The Mamenako is a strange, fluted, parasitic alien, which latches onto the skull of a host animal and integrates it's self into the victim's central nervous system. Over the course of several weeks the Mamenako releases specialized enzymes which result in the growth or large egg sacks, in which generate thousands of young. Eventually these egg sacks burst, allowing the young to consume the host animal, before spreading out to find more hosts.

Mamenako are generally considered dangerous vermin by most sentient species, and usually are exterminated on sight. The method by which they spread from planet to planet is currently unknown.

Facecrab

FaceCrabs are the latest innovation in what has become known as the "designer clone" industry. Enterprising individuals can pay exorbitant amounts of money to have their DNA spliced and recombined to give their bodies strange shapes.

Communities of "FaceCrabs" have started autonomous collectives in deep caves beneath the sea. They often find themselves on the receiving end of discrimination due to their chosen "lifestyle."

Propeller Fish

Propeller fish are fish with strange, propeller-like structures on their tales and heads. These appendages allow them to fly through the sky as easily as they can swim through the water.

Glibtick

Glibticks are a race of creatures descended from parasites. They live in large, floating, organic cities, created from a building material made up of genetically engineered bacteria. These gigantic bio-cities float through space for decades until they encounter a planet with compatible life forms, after which they descend to feed on all organic matter. The Glibticks are feared throughout the universe for these planetary raids, but have thus far resisted organized campaigns to subjugate them.

Scradpoles

Scradpoles are small, airborne amphibians that have no hind legs. Like all amphibians they spend the first part of their lives in water, however unlike all others they have a strange ability to fly through the air. The method by which they remain airborne is currently unknown.