Binacle is modeled very closely after its real world basis:
This happens to be an animal I love more than almost anything else in the sea. Everything about barnacles is fascinating. They're crustaceans, like crabs and lobsters, but they've evolved to lose mobility and live more like a coral, glued in place, filter-feeding on plankton.
I couldn't be happier if we're really getting such an accurate barnacle pokemon; the only thing that would take me a little getting used to are the goofy human-like faces on Binacle.
I would much rather it have only eyes, without the little mouths and noses, or no faces at all, and just look exactly like the real thing.
It seems to be attached to a hunk of sand or rock. If it's not fake, and it evolves, it might be attached to something else later.
There are, however, barnacles who don't attach to anything at all; they grow a ball-shaped "float" that they hang from in the water! I suppose that might have made a little more sense for a pokemon version.