Aurelionite

The Aurelionite is an Unique Stone Titan Boss, found on the Gilded Coast in Risk of Rain 2. Once three Halycon[sic] beacons are activated, the Aurelionite spawns, but it cannot be harmed until all 7 beacons are activated. After considerable damage has been dealt to Aurelionite, the beacons deactivate, and require the player to activate all 7 once again.