A Gas cloud is an area of effect damage over time spell that behaves similarly to the Minor Spiritual spell, Call Lightning (125). This was once a spell employable by Wizards, but has since been replaced by other spells, and is now exclusively a creature maneuver.
Like most area of effect spells (such as Energy Maelstrom (710), Implosion (720), and Sandstorm (914), gas clouds take time to form (usually about 3 rounds). Gas clouds have very damaging lightning criticals, which can easily cause level 3 wounds and potentially kill and/or vaporize a player in one strike. Gas clouds will attempt to strike one random target per round, and may potentially strike other creatures in the room.
Be wary that creatures can "speed up" a gas cloud's formation if it should attempt to cast the spell again, in which case the cloud appears to take one less round to form.
The gas cloud's duration generally depends on the level of the casting creature. Its damaging capability tend to diminish over time, but can still have the same deadly effects up to its last bolt.
Killing a creature that has summoned a gas cloud will usually cause the spell to end prematurely.
End of Spell