Lol well I used to watch the series so I'm familiar with the characters quite a bit. I'm sure it's a coincidence but the design does sort of remind me of something I've seen before. Anyway, Rankurusu being an embryo Pokemon does kind of jump at me though. When I first heard rumors that it was Mew who was based on such a concept, I couldn't really see the similarities but with Rankurusu being incased in jelly and slime and who knows what else, it could be possible. I just realized that both Gochiruzeru and Rankurusu are Psychic types even though they look like Dark types and Water types, respectitively. So I guess that's another similarity
I think Rankurusu is epic, but definitley not mew epic. But I also think it should be a dark/water pokemon, it seems more fitting.