Golem, Cannon

Family: Golems

Large construct, unaligned

Armor Class 20 (natural armor)
Hit Points 210 (20d10 + 100)
Speed 30 ft.

24 (+7) 9 (-1) 20 (+5) 3 (-4) 11 (+0) 1 (-5)

Damage Immunities fire, poison, psychic; bludgeoning, piercing, and slashing from nonmagical attacks that aren’t adamantine
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned
Senses darkvision 120 ft., passive Perception 10
Languages understands the languages of its creator but can’t speak
Challenge 16 (15,000 XP)

Special Traits

  • Fire Absorption. Whenever the golem is subjected to fire damage, it takes no damage and instead regains a number of hit points equal to the fire damage dealt. However, if it fails its saving throw against a fire spell that deals at least 20 points of damage, it must make a Constitution saving throw against the same DC. If this save fails, its cannon immediately backfires, dealing 6d6 bludgeoning damage to the golem (this bypasses its damage immunity).
  • 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.


  • Multiattack. A cannon golem has a magical cannon built into one arm rather than wielding a sword. It makes two melee fist attacks or one fist attack and one cannon attack.
  • Fist. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 20 (3d8+7 bludgeoning damage).
  • Cannon. Ranged Weapon Attack: +13 to hit, range 80/320 ft., one target. Hit: 33 (4d12 + 7) bludgeoning damage. When a cannon golem hits a target with its cannon, it can make a Strength (Athletics) check as a bonus action to shove that target, pushing it away and forcing it prone on a successful check. It has advantage on this check if the target is Medium or smaller.
  • Cannonade (Recharge 6). The golem shoots a cannon blast that fills a 60-foot line or a 15-foot cone. Each creature in that area must make a DC 19 Dexterity saving throw, taking 45 (10d8) bludgeoning damage on a failed save, or half as much on a successful one.


  • Cannon Punch (1/Turn). When a cannon golem scores a critical hit with its slam attack, as a bonus action it can make a cannon attack against the same target. It cannot use this ability if it already has made a ranged cannon attack or cannonade on the same turn.


A cannon golem is a technomagical construct enchanted into a massive heap of jagged metal in a humanoid form, its enormous cannon tracking movement with mechanical precision. A cannon golem’s internal workings are a mechanical labyrinth; its extradimensional pockets constantly process new black powder to fire its arcane weapon. A cannon golem stands 12 feet tall and weighs around 8,000 pounds.

Section 15: Copyright Notice

Sea Monsters (5E) © 2021, Legendary Games; Authors Michael Ritter, Michael “solomani” Mifsud, Robert J. Grady, Mark Hart, Jeff Ibach, Alex Riggs, Scott D. Young, Jeff Lee, Matt Kimmel, and Jason Nelson.

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