you can kill them with good tech (with enough hp and damage, like kodos) chims, maybe with trueshot or so can own em also easily earthquake if ur really desperate and they got like a whole base of arcanes =D althow this is easy to stop and got nerfed alot use the mage at creep shop (dont know its exact name), he has windwalk and can disable towers at a high range mass summons =D bears,trees, boars, lava .... shockwave with transmute maybe, althow this wont kill fast (u mute the workers and get mass gold, while they gotta keep spending gold on workers for base and towers) death tower, can kill workers and arcanes easily if u put em out of range. u can also use potion of focus to put 2 towers...