The Gas Guzzler was a soldier aboard the Mendacious Remembrance when it crash-landed in Blood Gulch. Afraid of leaving the ship, he slowly went insane and started to believe the ship could one day fly again. He hoarded all of the fuel aboard the ship, completely secret to Sam and everyone else in the canyon, until he killed Agent California in a frenzy.
Not too much later, Campbell and Das searched the ship for fuel, finding the body of California and soon enough coming across the Guzzler. A brief firefight ended in the Guzzler's death and the looting of all the Meniere's fuel.