Middle Earth Riddles: The Terror Continues

[Kalimac]

Oof...now I'm hoping the riddle wasn't *too* vague. All of the guesses are really ingenious (I mean, they're not answers I'd ever have thought of, if presented with this riddle) but I really didn't intend to stymie the thread to this point. Here are some hints:

(1) Both answers begin with the same letter (I've given this one before)

(2) The second "brother" is literally twice as large as the first, but not in a way that can be physically measured (what I mean is, don't try to use a ruler, tape measure, scale or anything like that, it won't work)

(3) Both of them physically stimulate the nerves. And no, they're not off-color, so don't bother [img]smilies/smile.gif[/img].

Hope that helps. If this goes on much longer, would you mind if I just told the answer? Then you'll all know and can say in chorus "WHAT? How do get that answer from those clues?" [img]smilies/smile.gif[/img].