Aurelionite

The Aurelionite is an unique Stone Titan Boss, found on the Gilded Coast in Risk of Rain 2. Once four 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 players to activate all 7 once again.