Digging hole to hell. So much water :C
That is useless now because water evaporates when it reaches the hell world.
EDIT: Killed the eater of worlds again, Ball O' Hurt is beast againest it, Same with Blue Moon and Sunfury.
EDIT 2: Has anyone noticed? Demonite can be now mined but i belieave is only found deep in the chasms of the corruption.