Guardian. A cave guardian will only attack a creature if it poses a threat to the cave it guards, i.e a miner.

Natural camouflage. A cave guardian can seamlessly camouflage against the wall of the cave it lives in.

Multiattack. The cave guardian makes 2 attacks.

Warning tremor. The cave guardian sends a tremor through the cave to warn away a potential danger. A creature must succeed on a DC 10 intelligence check or become frightened of the cave and all its contents.

Rock-hard fists. Melee Weapon Attack: +4 to hit, reach 5 ft., 1 target. Hit: 6 (1d12 + 3) bludgeoning damage. 

Body slam. The cave guardian rears up in response to an attack, slamming down again and dealing 2d6 bludgeoning damage to all creatures within 10 feet of it.