Oh boy, VFX! So I've got one concept that's really inspired me to do this.
It's a water fist(s) flying at an opponent. A simple build-up of the character rearing multiple arms back then unleashing them in a relentless assault.
I've thought of a couple variations of this too:
Making a right - left - uppercut
-or-
Fist pounding the ground causing waves outward
As for the second idea, I'm a bit unsure as to what I'll follow through with but for idea's I've got;
1) Swords of light raining down in an area
2) Ribbon whipping out, wrapping around the target, and pulling them in (Can't show animation on balls)
3) Cage of weapons entrapping an enemy
I'll put up some images in the near future!