The Noble gasbagon is a fatter, flightier version of it's breathy brethren. This gassy green goon has much the same attacks as it's dragon kin, able to rain down a Fiery Breath on the battlefield and simply squash foes with their sheer strength and size.
Dragons blown up to blimpish porportion. Full of floaty gas, who knows how far one would fly if you pulled out that tantalising cork at the tip of its tail...
The "noble" part of the Gasbagon doesn't refer to having an upstanding nature, but is actually a pun involving the noble group of gaseous chemical elements. "Gas bag" is an idiom that refers to overly talkative and boastful people, with the "n" in the Gasbagon name making them sound more like the dragons they bear resemblance to.