Incendiary Cloud

An Incendiary Cloud spell exactly resembles the smoke effects of a pyrotechnics spell, except that its minimum dimensions are a cloud 10 feet tall, 20 feet wide, and 20 feet long. This dense vapor cloud billows forth, and on the third round of its existence begins to flame, causing 1-2 points of damage per level of the spellcaster. On the fourth round it inflicts 1d4 points of damage per level of the caster, and on the fifth round this drops back to 1-2 points of damage per level as its flames burn out. In any successive rounds of existence, the cloud is simply harmless smoke that obscures vision within its confines. Creatures within the cloud need to make only one saving throw if it is successful, but if they fail the first saving throw, they roll again on the fourth and fifth rounds (if necessary) to attempt to reduce the damage sustained by one-half.