The Balrog

[Boo Radley]

Originally Posted by Pitchwife

Why did the Watcher in the Water grab Frodo, of all the Fellowship? Did it just feel some attraction from the Ring...?

This is what I've always believed. The Watcher could sense the power of the Ring and was attracted to it. Likewise, the Balrog, instead of being awakened (Or made aware of the party) by Pippin's dropped rock, also might have sensed the Ring and as the Ring contained quite a bit of Sauron's power, might have thought Sauron himself had come to Moria.