Cobalt Golem

Huge construct,

Armor Class

21 (natural armor)

Hit Points

300 (24d12 + 144)

Speed

walk 40 ft.

Damage Immunities

fire, lightning, poison, psychic; bludgeoning, piercing, and slashing from nonmagical weapons that aren't adamantine

Condition Immunities

charmed, exhaustion, frightened, paralyzed, petrified, poisoned

Senses

darkvision 120 ft.

Languages

understands the languages of its creator but can't speak

Challenge

18

Proficiency Bonus

+6

Conductive Body

Whenever the golem is subjected to lightning damage, it takes no damage. Instead, its weapon attacks deal an extra 11 (2d10) lightning damage until the end of its next turn. Also until the end of the golem's next turn, any creature that touches it or hits it with a melee attack while within 5 feet of it takes 11 (2d10) lightning damage.

Immutable Form

The golem is immune to any spell or effect that would alter its form.

Magic Resistance

The golem has advantage on saving throws against spells and other magical effects.

Magic Weapons

The golem's weapon attacks are magical.

Actions

Multiattack

The golem makes two attacks: one with its slam and one with its sword, or it uses its Magnetic Pulse and then its Spinning Cleave.

Slam

Melee Weapon Attack: +15 to hit, reach 5 ft., one target. Hit: 25 (3d10 + 9) bludgeoning damage.

Sword

Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 28 (3d12 + 9) slashing damage.

Spinning Cleave

The golem makes a sword attack against each creature within 10 feet of it.

Magnetic Pulse (Recharge 6)

The golem raises its arms and unleashes a magnetic pulse. All unattended metal objects within 30 feet of it are pulled to an unoccupied space within 5 feet of the golem. Each creature wearing metal armor or made of metal within 30 feet of the golem must succeed on a DC 20 Strength saving throw or be pulled to an unoccupied space within 5 feet of the golem, then fall prone.