upgrade rage skills, luck or something else untold?

[taltamir]

acid rain was bugged before 1.65 and did waaaaay more damage then it should have, ESPECIALLY if you were fighting a special enemy (aka, the more stacks on the map, the more damage) and if you were using wait it also increased its damage.

But the main useage for it is to hit your OWN troops who have magic spring on them to recharge mana later on... especially past turn 20. Ofcourse, that is not a big deal unless you are trying to do something like, say, beat the game with 0 losses (been done, very interesting thread)