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.

In this area, you can find blue gems that can be destroyed. The first and second doesn't anything but after you break the 3rd a warning message will show, later if you break the 4th it will summon a unique boss near an altar in the center of the map. Defeating it will drop in the same pedestal a rare item to each player. If it the first time you defeat the boss it will also complete the Challenge Guidance Offline, unlocking Loader. Destroying more gems after summon the boss will do nothing else.

As one of the last stages, taking the Teleporter will send you into the loop, starting again in one of the first stages you previously visited.