Solidify Air - Witch

By means of this spell, the witch causes the atmosphere to condense and solidify into a porous, translucent substance that is dense and hard as stone. On the first round, the air in the affected area becomes misty and thick, equivalent to a fog cloud. By the third round, has thickened into solid fog, reducing movement to but one foot per round. By the fifth round, the air has set and hardened, trapping any creature still within the area as if it was encased in solid rock. The solidified air is porous enough to allow breathing, and carries speech and sound as well.

The substance is not affected by dispel magic or any similar spell. Furthermore, the witch can command the solidified air to become non-porous, smothering those within it in a single round or can command the solidified air to turn to fog, releasing the trapped creatures (but reducing their visibility as normal fog). No saving throw is given against this spell, which lasts until the witch commands it to dissipate or is slain.