[OmikronWarrior]

I'm not entirely sure, but Paralysis is so overwhelmingly effective its hard to justify any other approach. Yes, you get mindburn at thau-2, but thats only 12 damage, hardly enough to quickly take out 20+ mammoths. 60 points of paralysis damage means roughly 30 rounds of not doing anything, and your astral mages can cast it with out any boosters. Another option is False Fetters (A2, Alt-1), but that has to be used close to the front and gives the trampler a chance to break it every turn, where as a paralyzed trampler is pretty much dead.