When triggered, a Gas Bomb or Gas Cloud trap surrounds the party with a miasma of poisonous gas.  This usually results in most, if not all, of the characters in the party being poisoned.

Overall, there's nothing really special or devestating about this trap.  As long as the party has a quick way back to the Castle or a priest with a lot of Latumofis (cure poison) spells, this trap is relatively harmless.  If the party is lost, however, you'd better start figuring out which of your strong characters can carry the rest of the party home by himself, and keep healing him as long as your priest is able.

This trap first appears at mid-level in the dungeon and can be found regularly in the deepest recesses.