A large army deciding to spend a ****load of gems to take out a bit of PD, that's just funny.
My communion master deciding to cast bone grinding (4 times!) instead of the scripted undead mastery, that's quite something else. Then, to add insult to injury, once his script ran out, he decided to use his leftover gems (he had gems left because he cast the cheaper bone grinding instead of undead mastery) on undead mastery...
I have to say I don't know what to do if undead mastery doesn't get cast here...