The subject and all its gear become insubstantial, misty, and translucent. Its material armor (including natural armor) becomes worthless, though its size, Dexterity, deflection bonuses, and armor bonuses from force effects still apply. The subject gains DR 10/magic and becomes immune to poison, sneak attacks, and critical hits. It can't attack or cast spells with verbal, somatic, material, or focus components while in gaseous form. This does not rule out the use of certain spells that the subject may have prepared using the feats Silent Spell, Still Spell, and Eschew Materials. The subject also loses supernatural abilities while in gaseous form. If it has a touch spell ready to use, that spell is discharged harmlessly when the miasmatic form spell takes effect.

The target's vaporous body is dangerous to creatures that touch it. A creature can make a Fortitude save (DC 14 + your Intelligence modifier) on its turn to resist the vapors. When you cast this spell, you select one of the following options.

Stinking cloud: The target's body nauseates creatures that fail their saving throws, as stinking cloud (Fortitude negates, see text). This form of the spell does not require a material component. This condition lasts as long as the creature is in the target's body and for 1d4+1 rounds after it leaves. (Roll separately for each nauseated character.) Any creature that succeeds on its save but remains in the cloud must continue to save each round on your turn. This is a poison effect.

Poisonous cloud: The target's body is deadly poison, dealing 1d2 points of Constitution damage to creatures that fail their saves (Fortitude halves). This form of the spell requires a material component.

A miasmatic creature can't run, but it can fly at a speed of 10 feet and automatically succeeds on all Fly skill checks. It can pass through small holes or narrow openings, even mere cracks, with all it was wearing or holding in its hands, as long as the spell persists. The creature is subject to the effects of wind, and it can't enter water or other liquid. It also can't manipulate objects or activate items, even those carried along with its miasmatic form. Continuously active items remain active, though in some cases their effects may be moot.