What did the gargoyles represent in Bran's dream?

The gargoyles represented the Lannister twins. This is the part of the dream in question: > There was no way to go but up. Far above him, outlined against a vast pale moon, he thought he could see the shapes of gargoyles. read more

Gargoyles were originally used as water spouts on religious buildings, but quickly came to be seen as a way to ward off evil spirits because of their grotesque look. The gargoyles' grotesque look was modeled off of the idea of hell, and was used as a way to help illiterate people understand what hell was and what it could do to a person. read more