From Aloniverse

Gaz is a flammable natural methane gas, collected in bottles by wizards, witches and enthusiastic hobbyists. Indeed it was an enthusiastic hobbyist on Topnodon who let one go while too close to the fire. Subsequently the enthusiast blasted into the sky and vanished through the portal of Topnodon. He ended up lost and somewhat bewildered in Lugunter. Sometimes the portals do more than just transfer beings from planet to another, sometimes they change the being from one thing to another, in this case the enthusiast on arrival in Topnodon became Carl the Carpet