A bank of fog billows out from the point the character designates. The fog obscures all sight, including darkvision, beyond 5 feet. A creature within 5 feet has one-half concealment (attacks suffer a 20% miss chance). Creatures farther away have total concealment (50% miss chance, and the attacker can't use sight to locate the target). The fog is so thick that any creature attempting to move through it progresses at one-tenth normal speed, and all melee attack and melee damage rolls suffer a -2 penalty. The vapors prevent effective ranged weapon attacks (except for magic rays and the like). A creature or object that falls into the fog is slowed, so that each 10 feet of vapor that the creature or objects passes through reduces falling damage by 1d6.
Each round, starting when the character casts the spell, the fog deals 2d6 points of acid damage to creatures and objects within it.
Only a severe wind (31+ mph) disperses these vapors, and it does so in 1 round.