Methanosian

Methanosians
Methanosians are from the swamp planet Methanos (both referring to methane). Methanos is described as a swamp planet that has an atmosphere that is toxic to most life forms. Methanos also has large underground deposits of methane gas that sometimes escape and create geysers of flame that to jumps up to twenty feet into the air.

Methanosians are descended from carnivorous swamp plants, but at some point in their evolution Methanosians evolved into herbivores. Breaking down rotting plant matter in their pitcher plant-like stomachs to produce the flammable gas methane which they used for their fire attacks.