Siren's Call

The Siren's Call is an environment that takes place as one of the 4th stages in Risk of Rain 2. The other is Abyssal Depths.

Nests of eggs spawn on this level at a few predetermined locations. The eggs can be destroyed. The first and second do not do anything, but after the player or enemies break the 3rd, a warning message: "you hear a distant whirring" will appear. Later, if the 4th breaks, the Alloy Worship Unit, a unique boss, spawns near the altar at the center of the map, accompanied by the message: "the whirring grows louder".

Defeating the Alloy Worship Unit will cause a rare item to drop from the altar for each player. If it is the first time a player has defeated the boss, it will also complete the Challenge Guidance Offline, unlocking Loader. Destroying more eggs after summoning the boss will do nothing else, besides healing players near the eggs.