"The walls moved!" Krunis exclaimed. This he was sure of it this time.
"Of course they did. They are trying to accommodate the additional room needed for tonight." Xarn returned matter-of-factly.
Living stones are tuned to one master to do his bidding.
Believable magic, like ordinary physicis, operates according to some invariable laws that always result in some kind of cost or "bounce back". The grater the magic, the more it should cost the character physically, emotionally, and spiritually.