My players didn’t tango with these guys. They made sure not to do anything that would in any way be seen as “disturbing their work” and got by them just fine. The tractor beam is inspired by the original Workerbot from Expedition to the Barrier Peaks. I added it as a nod to the original adventure.
HEAVY REPAIR DRONE
Huge Construct (robot), unaligned
Armour Class 14 (skymetal chasis)
Hit Points 265 (16d12 + 160) plus 65 hp force field.
Speed 30 ft., climb 30 ft. The drone can also levitate using its tentacles to move itself a long.
STR 30 (+10) DEX 9 (-1) CON 30 (+10)
INT 15 (+3) WIS 8 (-1) CHA 10 (+0)
Skills Cybertheurgy +15
Damage Resistances bludgeoning, piercing, and slashing from nonmagical weapons that aren’t adamantine.
Damage Immunities necrotic, poison, psychic
Damage Vulnerabilities lightning
Condition Immunities charmed, frightened, paralysed, petrified, poisoned, and stunned
Senses Darkvision 60 ft., passive Perception 9
Challenge 13 (10,000 XP)
Gift of the Machine God. As a creature of technology heavy repair drones gain many damage and condition residences and immunities but they are also susceptible to electrical attacks.
Magic Resistance. The heavy repair drone has advantage on saving throws against spells and other magical effects.
Repair Robot. As an action that does not provoke an attack of opportunity, a heavy repair drone can repair damage dealt to either itself or an adjacent robot, healing the target of 10 (2d10) points of damage
Self-repairing. The robots nanites repair the robot continuously. It heals for 10 hit points per turn until returned to full hit points so long as it has 1 hit point left.
Sturdy Construction. The heavy repair drone is ruggedly built and has a hardness of 10.
Multiattack. The heavy repair drone can makes three machine tentacle attacks. It may replace one attack with Tractor Beam.
Machina Tentacles. Melee Natural Weapon Attack: +15 to hit, reach 10 ft.; one target.
Hit: 20 (3d6 + 10) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained. The heavy repair drone has ten tentacles, each of which can grapple one target.
Tractor Beam. Heavy repair drones are fitted with a heavy-duty tractor and repulser beams. This acts as the telekinesis spell (PHB pg. 280) with a DC of 18. The drone may move a creature or object that fails its Strength ability check up to 30 feet and they become restrained.
Nicknamed “clocktopuses” for their mechanical tentacles and bulbous central hubs, these drones focus narrowly on their assigned tasks and ignore intruders unless the intruders interfere with their work.