I actually kinda like this Superhuman Water thing as a concept, this episode just used it in a really throwaway/fillery way.
In bed last night I was imagining this whole saga where this really strong dude and his goon squad is looking for this secret thing that was said to be stored away by this really ancient (but now long dead) strong guy. The secret thing was rumored to be able to turn one into the ultimate warrior. They follow some leads. The Z squad is also trying to get help and follow their own leads so they can find this thing before the bad guys. Maybe something lead the villains to Earth, so that the good guys already had an encounter with them and know what's up with them.
Anyway, they go to some other planets, discover that the secret thing stored away by the ancient dude is the superhuman water. They figure out what planet it's on, but maybe not exactly where it is. Strong bad dude, his goon squad, and the Z-fighters all head there. Some things happen. The main bad dude maybe gets defeated or something, but one of his not as strong but still competent goons get to the water anyway. Then it absorbs him, turns him into an even more powerful version of himself. Maybe at some point, one of the good guys get absorbed too (like Vegeta in this episode, but it could be anyone). Fights go down. It turns out that the superhuman water is actually semi-sentient with the soul of the ancient strong dude who was said to be the one who stored it away in the first place. Somehow, the ancient strong dude gets fully revived by the water being put into action. Either he turns out to be the super strong last boss of the arc, or he's actually good and stored it away for the sake of the universe, and helps the Z-Squad fight off the extra powerful goon and/or evil Z-squad member.
And then of course have a lot of interesting character dynamics and encounters based around this outline.
#CANON
edit: the last thing i wanted was for my fanfiction to be at the top of a page