Might not be a good idea, also might have been suggested.... Would require the extra suggestion.
Submit-
Tidal Wave, Weapon: Deal 5 damage,
(
for upped) target aquatic creature gains momentum.
Submit-
Liquefy, Either spell or permanent with higher activating cost (3-2), target creatures becomes aquatic.
I know it's pretty much a twin idea. (thought about shield first, but
already has a great shield and it would be too much like Wings) Also it could be for every creature when upped. I hope aquatic becomes reality soon as a new passive ability. (So such cards could be built around it)