The water from Fluidity/Hydroventure should be a character in the next Smash game.
I smell an opportunity to implement tilt controls! Innovation!
It depend is Fluidty/Hydroventure is a Nintendo title.
It's published by them, so I believe it could make it in.
Not as a playable character I'm guessing, but seeing it included as an Assist Trophy (or item) would be cool.