From Diablo Wiki
The Ancient Device is not an event, but it contains so many variations of content similar enough to an event to be considered for the category. Much like an event, the Ancient Device often houses a dungeon, and there's also an achievement called Wheel of Misfortune for fulfilling every possible variation that the device can offer.
There are ten different outcomes that the device has to offer, from a treasure chest to a dungeon with a killer chicken, and they are chosen at random, roulette-style.
 Finding the Device
The device is found in the Desolate Sands of Act II, either in the mid-southern portion of the zone, or in the northern portion, if it spawns at all. It shares a spawning chance (and location) with two other very large map tiles.
The map to the right shows the two possible locations where the device can spawn, and also a route to find it (as it will take many tries in order to get every outcome). It is suggested to begin the quest The Black Soulstone and take the waypoint to the Ancient Path. Once there, if the player heads north to the beginning of the Desolate Sands, they will get a checkpoint.
The checkpoint allows easy access to the route described above, as the waypoint will spawn in wildly variable locations around the zone, and can make it hard to tell where the player is upon loading the game.
 Possible Outcomes
The below possible outcomes of using the ancient device are not listed in any particular order. By appearances and testing, it's possible that they all have the same probability to spawn.
- The Veiled Treasure - a small dungeon with numerous Resplendent Chests inside will spawn, complete with elite packs. There is also a high probability of a Treasure Goblin spawning, as well.
- The Fowl Lair - This dungeon contains an enemy that is most horrendous and revolting. With grease.
- A pile of Diseased Bodies will spawn, which in turn will spawn a group of Betrayed.
- A group of Bone Warriors will spawn (and can spawn as elites).
- A group of Vile Swarms will spawn.
- A plain treasure chest will appear, with a randomized drop.
- A Resplendent Chest will spawn.
- Gold will rain down in small doses, like that of the Countess's chest in Diablo II.
- A Superunique Sand Golem named Ernutet, Guardian of the Veiled Treasure will spawn, along with two companions. He has the illusionist boss modifier.
- An ancient urn will spawn. It breaks easily.
- Nothing all appears on the platform.
A video by user lyesalot showing each outcome of the ancient device:
|Quests & Events of Diablo III  Act I Act II Act III & Act IV Act V|
|Act I Quests||Act I Events |
• The Fallen Star
|Act II Quests||Act II Events |
|Quests Act III||Events Act III||Quests Act IV |