Cloudkill
Foul and poisonous vapors boil from the thin air, forming a cloud 15 feet in radius. The cloud moves away from the caster at a rate of 6 feet per minute unless its direction or speed is affected by winds. Unusually strong gusts can dissipate and destroy it. Poison-laden, the horrid mist is heavier than air, and thus sinks down any pits or stairs in its path. This spell affects only creatures with 5 or fewer HD.