>>52789287the idea is supposed to be that an unrelated pokemon evolved to have the same appearance as the tentacool and diglett lines
but in practice they have the same exact stats and mostly equivalent learnsets so there really isn't anything separating them from regionals outside of egg groups and a distinct dex slot
the concept would have been much more interesting if they played with it in some way, like having the base form bear the resemblance while the evolution deviates much more drastically, or having the base form be unrelated while it slowly evolves into something that further resembles the line its mimicking
as it is now it's just a reskin of the original pokemon the same way normal regionals are, only this time they can pretend it's something deep and clever because it plays with a slightly different evolutionary concept