Cloudkill

Cloudkill was a conjuration or evocation spell that filled an area with a extremely lethal cloud.

Effect
Cloudkill would release a yellowish green cloud that was heavier than air so it would always sink to the ground or into holes. When cast, the cloud would travel away from the caster and could be broken apart by strong winds or dense vegetation. The cloud would instantly kill "weak" creatures and greatly injure stronger creatures with its poison. It did not matter if the creature held its breath as the poison would still affect it.

After the Spellplague, the cloud would only harm targets and could be moved by the wizard who also needed to sustain it. The post-Sundering version had some of the same features as the older versions, like being heavy and affecting creatures whether they held their breath or didn't need to breath. This version also lasted for 10 minutes and moved 10 feet (3 meters) every 6 seconds away from the caster. If used with a higher spell level, it would cause more damage.

Components
Only vocal and somatic components were needed.