Clockwork Geosurveyor Mek

Immutable Form. The clockwork automaton can't shape-shift.

Magic Resistance. The clockwork automaton has Advantage on saving throws against spells and other magical effects.

Tunneler. The mek can burrow through solid rock at half its Burrow Speed and leaves a 5-foot-diameter tunnel in its wake.

Multiattack. The miner makes two attacks, using Drilling Leg or Pick Leg in any combination.

Drilling Leg. Melee Attack Roll: +10, reach 10 ft. Hit: 15 (2d8 + 6) Piercing damage. If the target is touching the ground, it is knocked Prone and Restrained by the mek’s pointed leg. While Restrained in this way, the target takes 15 (2d8 + 6) Piercing damage at the start of each of its turns, and the mek can’t make Drilling Leg attacks. The Restrained condition ends if the mek moves, makes a Drilling Leg attack, or is destroyed. The target or a creature who can reach it can use an action to pull the target away from the drill, ending the Restrained condition and dealing 15 (2d8 + 6) Piercing damage to the target in the process.

Pick Leg. Melee Attack Roll: +10, reach 10 ft. Hit: 17 (2d10 + 6) Piercing damage. Nonmagical armor worn by the target takes a −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10. The penalty can be removed by casting the Mending spell on the armor. 

Throw Ores (Recharge 6). Dexterity Saving Throw: DC 18, each creature in a 30-foot Cone. Failure: 44 (8d10) Bludgeoning damage, and the target is Blinded until the end of its next turn. Success: Half damage only.

Shockwave (Recharge 6). Dexterity Saving Throw: DC 18, each Medium or smaller creature in a 30-foot-long, 5-foot-wide, and 30-foot-deep Line. Failure: 10 (3d6) Bludgeoning damage, and the target falls into the crevice Prone. Success: The target is shunted 5 feet into an unoccupied space and does not fall into the crevice. If a creature doesn’t have an unoccupied space within 5 feet of them, it fails the saving throw.