Living rock patriarchs are huge creatures that randomly spawn in the Living Rock Caverns. When a patriarch appears, any player around the area can attack it, but only the first player who fights it can tag it to get its drops. Protect from Melee is recommended, as they are quite powerful for their combat level. Even a high-levelled player with good armour might require food or soulsplit to defeat it. When slain, the patriarch always drops its entire drop table (which consists of four unique items in various quantities) at once. This drop is quite valuable, so whenever a player sees one, they should attack it as quickly as possible.
Despite common belief, their spawn is not triggered by killing living rock creatures, but rather the number of people in the world. They spawn erratically every 2 hours, tending to appear in the south-west, south-east, and north-east corners of the cavern.