Sometime around 95 I was watching a movie on TV with my dad. I want to say there was a drought and some type of deformed people or civilization that lived underground. A regular person cme down and instigated them starting a fight with whoever controlled the water. Something happened where the water controller sent one of their “people” back in a box to send a message? And they went to war…
Vaguely sounds like “The Time Machine”. 1960.. but they don’t fight over water..
Maybe”Dune”(1984)? Just a crazy guess.