"Spell or Enchantment.
Choose four connected hexes. Those four hexes are turned into Ocean instead of their original terrain type. Land based units on these four hexes become undimmed, but must use their next action to move out of the four targeted tiles. If they fail to move they will drown."

Cost: 7 flux.

Domain: ?? 2 or 3 Neutral or Sylvan??

while on this idea of terrain changing how bout
'eruption'
2/3 mountain folk
cost - 7ish.
changes adjacent land around mountain into mountain terrain, unless sea, where it changes into desert.

sorta like 'wider woods' for the mountain folk.

_________________

I dont think so rumble. The mountian folk already have enough terrain editing options.

_________________
If you ever need help/training/tips etc just ask.