Ball of Lightning for the win
Max your pet Dragon's Ball of lightning ability and get some Gorguanas. Mark of Blood on the Brontors and create the ball of lightning somewhere close to them. Now watch the carnage! It is possible to kill 96% of that stack in a hit and inflict a wicked "damage" (it's not damage, it's how much HP the Ball of Lightning killed) - you can refer to my signature for additional info... I wasn't bragging, I simply put it there as an example of a very, very useful trick in the game.