A large and diverse group of predatory Hemiptera or "true bugs," these stalkers use a tubular beak to inject paralyzing digestive enzymes and drink the contents of other insects. Morbidly, a few species even cover themselves in the corpses of their prey for camouflage.
Pokétential: a bug type wearing pokémon bones, naturally. If they want to get creative, it could specialize in the metallic bones of steel types. The first "super effective" hit could simply destroy this collected armor, reverting it to a normal bug without losing health.
The world's largest nocturnal primate, this haunting Madagascan lemur uses its long, spidery fingers to fish wood-boring insects from their burrows. Shy and harmless, its goblin-like appearance has unfortunately lead superstitious locals to kill the creatures on sight, convinced that they possess dark and horrifying powers.
Pokétential: I have an urge to suggest something less obvious, but how could it really be anything other than a dark type? Give it even longer, creepier fingers than the real thing!
As I've expounded upon before, there's a lot more to these bizarre, stationary crustaceans - the Cirripedia - than meets the eye. Some are mind-controlling crab parasites, some colonize toxic undersea "volcanoes" and all of them are weird as hell.
Pokétential: some have suggested that Shuckle is already a barnacle, but it's hard to tell, and there's plenty more that could be done with the idea. Why not a dense coating of them controlling a "zombie" crab, fish skeleton or even a whole sunken ship? Alternatively, we could have a volcano-like water/fire cirripede. You could call it Barnacano!
The name "basilisk" is derived from a mythological reptile able to kill prey just by looking at it, though these animals have also been called Jesus lizard for the ability of smaller specimens to run madly atop water when startled.
Pokétential: a finned water-walking lizard seems like a shoe-in for a water type "starter" pokémon, though it could just as easily be a fire type lava-dweller...or a flying type able to "run" through the air with huge, winglike feet. Huge, colorful eyeballs could play on the mythological aspect.
We've already got one sea-star pokémon, but these deep-sea creeps belong to the brittle stars, and are quite a bit stranger. Their tentacles branch literally hundreds of times, and are lined with tiny hooks to trap small prey in a living, barbed web.
Pokétential: the largest of all basket stars is Gorgonocephalus, literally meaning "Gorgon's head." It's just asking for a big, creepy eyeball in its center that paralyzes foes, while the rest of it could look like a spider's web of spiny tendrils.
Distantly related to the bizarre anglerfish and frogfish (more on those later!) these strange animals are completely adapted for "walking" on the sea floor and make rather poor swimmers, their rear fins adapted into chicken-like legs. Many have a chemical lure just above the mouth.
Pokétential: Most species have a saucer-like shape or even a long, pointed snout. Either would lend well to a blade-edged water/steel type.
BLIND CAVE SALAMANDER:
Several species of salamander are so adapted to subterranean waters that they have completely lost all pigmentation and any trace of eyes, an evolutionary path called troglobitism shared by many different creatures who have adapted to specific cave systems.
Pokétential: I'm really rather disappointed that Zubat is still one of the only eyeless subterranean pokémon, and gets eyes as soon as it evolves into Golbat. A proper troglodite is long overdue, though it might be interesting if the salamander's evolution regained eyes somewhere other than its head.
This famous photograph of a deep sea blob sculpinisn't how they look when they're alive, but true to their name, their bodies consist mostly of flabby, gelatinous skin with almost no muscle tissue. Floating in place for hours or even days, they simply swallow anything that floats by their mouths.
Pokétential: a stylized blobfish would probably take after the droopy-nosed corpse, but that's alright. It would make a pretty hilarious looking water type, especially if it crawls around on land like a living puddle. Like slowbro, it could compensate for terrible speed with impressive psychic powers. They have a lot of time to meditate, after all.
Reaching several feet in length, these predatory cousins to the earthworm dwell in tunnels on the sea floor, popping out to strike at passing fish with vicious scissor-like mandibles. Hairs along their edges can also deliver a paralyzing sting, and they shine vivid colors in sunlight.
Pokétential: they may be aquatic in the real world, but they would make an excellent basis for a gigantic desert-dwelling monster sandworm. The spice must flow, Ash!
Oh yeah, this list is going to be heavy on the invertebrates and especially arthropods. I suppose I should have gotten that out sooner. "Bugs" just make up the vast majority of life on Earth, they were part of pokémon's original inspiration and they have a lot of cool powers. Bombardier beetles are an especially striking example, able to spray boiling hot chemicals from their abdomens with explosive force and staggering speed; up to several hundred shots can be fired in a single second!
Pokétential: facing away from its opponents, this bug type could have a diverse arsenal of beams to blast from its gun-like posterior.