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 solid 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 solid fog is slowed, so that each 10 feet of vapor that the creature or objects passes through reduces falling damage by 1d6.
Only a severe wind (31+ mph) disperses these vapors, and it does so in 1 round.
The spell does not function underwater.