This is not your typical custom LEGO gun because it doesn't shoot bullets. It's pretty self explanatory, but in case your are unsure, the Fire Breather shoots fire. Lots and lots of fire. 

How does it work? Who cares! It looks awesome. 

Fire not included, but you can use a BrickWarriors Thraex Plume to make fire if you don't have a LEGO piece for it. 

The arsonist in this picture is wearing a RT Helmet and RT Armor. The poor guy on fire is wearing a Rhino Helmet and a Gladiator Pauldron.