This monstrosity ended up duelling the party and their tank. Was a fun fight.
Gargantuan construct (robot), unaligned
STR 29 (+9) DEX 14 (+2) CON 20 (+5)
INT 10 (+0) WIS 18 (+4) CHA 10 (+0)
Saving Throws Str +14, Con +10, Wis +9, Cha +8
Skills Cybertheurgy +8, Athletics+ 14, History +8, Perception +9
Damage Resistances cold, fire; bludgeoning, piercing, and slashing from nonmagical weapons that aren’t adamantine.
Damage Immunities force, necrotic, poison, and psychic
Damage Vulnerabilities lightening
Condition Immunities charmed, frightened, paralyses, petrified, poisoned, stunned
Senses Darkvision 60 ft., passive Perception 19
Challenge 13 (10,000 XP)
Combat Hardened. The annihilator’s advanced robotic frame provides a measure of protection against attacks. The annihilator has a damage threshold of 5. It reduces all damage per attack by 5.
Gift of the Machine God. As a creature of technology a deformed android gains many damage and condition residences and immunities but they are also susceptible to electrical attacks.
Unrepaired. The damage the robot suffered has done more than lower its hit points and reduce its hardness—it’s also rendered one of its chain guns inoperative, ruined its booster jets and its force field, and prevents it from using its chain gun to perform suppressing fire. Finally, if the robot suffers critical hit damage, it loses 1 point of hardness in addition to the regular effects robots suffer on a critical hit. Despite all this damage, though, the annihilator remains a deadly foe—and foreshadows a fight against a fully operational annihilator at the start of the final adventure in the Iron Gods Adventure Path.
Multiattack. The annihilator makes three attacks: two with its claws and one with its chain gun. It may also fire its plasma lance as a bonus action when available.
Claw. Melee Weapon Attack: +14 to hit, reach 15ft., one target.
Hit: 16 (2d6 + 9) piercing damage.
Chain Gun. Ranged Weapon Attack: +14 to hit, range 400 ft., one target.
Hit: 20 (2d10 + 9) ballistic (force and piercing) damage. The chain gun misfires on a natural 1 or 2. The annihilator must spend a bonus action to clear the jammed weapon, which can fire again the following round.
Plasma Lance (Recharge 4-6). The annihilator may fire a 120-foot-long line of plasma from its tail. All creatures in this area take 42 (14d6) points of plasma damage (half fire, half electricity; DC 18 Dexterity halves).
The annihilator damage core explodes when reduced to 0 hit points in a 20-foot blast radius of plasma. All creatures in this area take 42 (14d6) points of plasma damage (half fire, half electricity; DC 18 Dexterity halves).