In Elder Scrolls IV: Oblivion, there are "gas traps" which damage your health when you get near them.
It occurs to me that these "gas traps" should be flammable.
In Oblivion, they aren't. You can shoot a fireball or walk in carrying a torch and nothing happens.
As-is, the gas traps are practically harmless if you don't sit on top of them. They'd be far more deadly if they could be used as "flammable gas traps".