Life Bubble creates a shell of tolerable living conditions around the creature. This includes toxic atmospheres etc. Could a caster modify the spell to deliberately create a harmful atmosphere around an enemy? Rough homebrew example below,
Extraterrestrial Life Bubble
1st - level Abjuration
Casting Time: 1 standard action
Range: medium (100ft plus 10ft per level)
Targets: 1 creature per level (all must be within 30ft of each other)
Duration: 1 minute per level
Saving Throw: Will negates
Spell Resistance: yes
As per Life Bubble you surround the target creature with a constant and movable 1 inch shell of smoky sulphur dioxide atmosphere. Each round the creature can make either a Will save to dismiss the spell or a Fortitude save to breath; if a creature chooses to make a Will save they are considered to have failed their Fortitude save. On a successful Will save the spell dissipates and the creature suffers 1 more round of toxic atmosphere. While affected by the toxic fumes the creature must succeed a Fortitude saving throw each round (DC = 15+1 per previous check) or spend that round choking and coughing; it can do nothing else (unless the creature has chosen to attempt a Will save to dispel the effects). A creature who chokes for 2 consecutive rounds takes 1d6 nonlethal damage. The caster can end the spell as a free action at any time during their turn however if he chooses to do so all creatures under the effect are released.