This spell generates a bank of fog, similar to a fog cloud
except that its vapors are ghastly yellowish green and poisonous.
They 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 ones breath doesnt
Unlike a fog cloud, the cloudkill moves away from the
character at 10 feet per round, rolling along the surface of the
ground. (Figure out the clouds 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 den or sinkhole openings. It cannot penetrate
liquids, nor can it be cast underwater.