This is a lost artifact, known only through ancient stories of long-deceased ancestors, and has not been discovered in Ur. When Gulliver decided he needed something to steel his nerves before the cheaper domestic dragon-flights of the beforetimes, he created a new type of carry-on bottle to put it in. Made by rubbing waxy egg plant leaves until seethrough, sewing with chicken-leather and attaching a beak for a lid, it was a breakthrough in lightweight emergency booze carriage.