It occurs to me, if they were to accidentally swallow their respective plushies, would the plushies continue absorbing the water within them, thus generating even more to fill them, which is in turn absorbed, for an ever escalating feedback loop?

That’s a good question but the thing is, everything the dolls eat or suck up, gets magically teleported over to the real ones, if I were to eat myself, nothing would happen except for now looking even fatter as I have a voodoo doll inside me and many tons of water. Napther on the other hand... he’s weird... it’s possible your theory might actually work with him just cause magic and Napther don’t mix well.

Don't mix well, or mix far too well~?

Hmmm... another good question... guess it depends who you ask. If not taken carefully we might just have a giant infinite growing Napther on our hands. Maybe. Cuetz would have his magic cut out for him.

I, for one, see nothing wrong with an OmniNapther~

Of course, why am I not surprised. Then again, I suppose Napther is a good candidate for that, hmm I wonder if he knows he can do this... eh he’s too occupied with having literally half a ocean inside him.