A bank of yellowish green poisonous 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's vapors kill any living creature with 3 or fewer HD (no save) and cause creatures with 4 to 6 HD to make Fortitude
saving throws or die. Living creatures above 6 HD, and creatures of 4 to 6 HD who make their
saving throws, take 1d10 points of
poison damage each round while in the cloud. Holding one's breath doesn't help.
The cloudkill moves away from the character at 10 feet per round, rolling along the surface of the ground. (Figure out the cloud's new spread each round based on its new point of origin, 10 feet farther away from the point of origin where the character cast the
spell.) Because the vapors are heavier than air, they sink to the lowest
level of the land, even pouring down openings. It cannot penetrate liquids, nor can it be cast underwater.
A moderate wind (11+ mph) disperses the fog in 4 rounds; a strong wind (21+ mph) disperses the fog in 1 round.