Water
Water quenched thirst. Water kept you clean. Water was a source of life to everyone in Oz and the Other World.
Well, almost everyone…
The liquid burned the Witch. She didn't dare to drink it; it would scorch her insides. It would kill her if she bathed in it.
To the Witch water was the source of death.
She wondered, as the farm girl from Kansas soaked her to the bone, if water affected others the way it did her. She supposed it didn't; she hated the thought of being like others.
Though it was hard to think as she burned like she was being drenched in acid…
As she died, she saw herself being melted over and over and over...and she saw herself as a child, accidentally being splashed when it was raining. The child cried, and her tears burned her.
"Water... it hurts...Mother, Father, make it stop!"