The Golden Chamber is an event that can be found in Ruins of Corvus in Act V of Diablo III, in Campaign Mode or Adventure Mode.
It requires the player to kill five unique Flesh Golems, one at a time, always in the same order: Pyresh, Arcuss, Miasma, Wahr, and Troven. Killing them all will open the door to the vault, inside which there is a Resplendent Chest and a sack with The Testament of Rakkis.