Cairn Creeper

False Appearance (Object Form Only). While the Cairn Creeper remains motionless in the form of the pile of stones, it is indistinguishable from a normal cairn.

Earth Glide. The creeper can burrow through nonmagical, unworked earth and stone. While doing so, the creeper doesn't disturb the material it moves through.

Grasping Earth. The creeper has advantage on attack rolls against any creature grappled by it.

Multiattack. The Cairn Creeper makes two Stone Slam attacks.

Stone Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage. If the target is a creature, it is grappled (escape DC 14). Until this grapple ends, the target is also restrained. The Cairn Creeper can only have two creatures grappled in this way at a time.

Earthen Tomb (Recharge 5-6). The creeper targets one creature it can see on the ground within 30 feet. The target must succeed on a DC 14 Strength saving throw or be pulled partially into the ground and restrained as rocks and earth erupt and cling to them. A creature can use its action to make a DC 14 Strength (Athletics) check, freeing itself or another creature within its reach on a success. The earthen tomb is an object with AC 15, 20 hit points, and immunity to poison and psychic damage.