The Golden Chest gives you high-end loot. These even can be legendary items. You can open up the Golden Chest by using Golden Keys. These keys can be earned throughout the game but Gearbox Software will also hand out SHiFT Codes that give you access to them. The Golden Chest is located on Sanctuary 3.
The weapon in this video is the Legendary Jakobs Shotgun called the Hellwalker.
Resources:
Mark Zuercher
Never a legendary in gold chest the lie