I used this in one of my campaigns. Enjoy:
Living Iron Statue
Large construct, unaligned
Armor Class 19 (natural armor)
Hit Points 42 (4d10 + 20)
Speed 30 ft.
STR DEX CON INT WIS CHA
18 (+4) 9 (−1) 20 (+5) 3 (−4) 11 (+0) 1 (−5)
Damage Immunities poison, psychic;
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, and poisoned
Special Defenses: bludgeoning, piercing, and slashing from nonmagical weapons do normal damage. If the living iron statue is struck with a nonmagical metal weapon the attacker must make a DC 15 STR save or the weapon becomes stuck in the body of the living iron statue. The weapon is retrievable when the statue is killed.
Senses dark vision 120 ft., passive Perception 10
Languages understands the languages of its creator but can’t speak
Challenge 3 (700 XP)
Actions
Multiattack. The living iron statue makes two slam attacks.
Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: (1d8 + 4) bludgeoning damage.