[aragornreborn]

If you think about it, being able to change one's size and shape at will would make the weilder of such powers practically invincible if he didn't mind constantly changing, looking a tad ridiculous, or ruining a good story. Also, they could just stay ridiculously large in the first place making an assault upon them impossible. So, it would make sense if there were some limits on this morphing ability of these creatures. Yes, yes, I know this is just a book, but... So, the ability to change size should not be used as a solution because either there are limits or Tolkien was a sloppy story-teller, his work is faulty, and there's no point or possibilit of intelligent debate or definite conclusions anyway.