Cave-in Boulder

Cave-in Boulders are a special kind of Boulder that can be carried. They can also be mined for rocks using a Pickaxe. The boulders that drop during Cave-ins can be carried, much like Suspicious Marbles, and can even be brought outside the caves. 
During an Antlion attack, big boulders will drop on locations close to the players inside caves, damaging them if hit, destroying any Structures nearby, and potentially blocking the way. Like Sinkholes, they can be prevented if the players occasionally give items to the Antlion.
After repairing the Ancient Gateway, boulders will also fall during an earthquake underground. During this time, boulders will not fall near structures.
They are also found on the way from Lunar Grotto to Ancient Archive.
vi:Cave-in Boulder