What about a deadly hail of small stones from the ceiling, high above? Might even make for a devastating spell, causing several small rocks to fall from an incredible height.
I think a lot of cool things can be done with a \"cave\" environment - there may be trees and grass around in the first couple levels, but it would get darker as you went down. Perhaps you\'d have larger, more sparse vegetation- giant tangles of roots, with some trunks reaching up towards the light of the crystal. Glowing fungus that lives off magical energy, or bits of crystal, might also provide some auxiliary light.
Given that Yliakum (or Hydlaa, can\'t keep \'em straight nowadays) is a giant stalactite, it\'s unlikely that there\'d be much seismic activity, but in the Labarinths there could be fiery crevices and caves choked with ash.