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Living Bog

Gargantuan ooze, unaligned

30 (+10) 6 (-2) 26 (+8) 2 (-4) 6 (-2) 1 (-5)

Armor Class 17
Hit Points 185 (10d20 + 80)
Speed 20 ft., swim 20 ft.
Saving Throws Constitution +12
Damage Resistances acid, cold, fire
Damage Immunities poison
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, poisoned, prone
Senses passive Perception 8
Challenge 11 (7,200 XP)

Special Traits

  • Boglike. A motionless living bog so closely resembles a stretch of boggy ground that a creature needs to succeed at a DC 20 Wisdom (Survival) check to spot one. The roll is made with disadvantage if the creature is not specifically searching for danger.
  • Enveloping Muck. The living bog can occupy another creature’s space and vice versa, and the living bog’s space is difficult terrain.
  • Combustive Burst. As a bonus action, the living bog can cause one of its swamplights to explode. Each creature within 25 feet of an exploding light must make a DC 18 Dexterity saving throw, taking 21 (6d6) fire damage on a failed saving throw, or half as much damage on a successful one.


  • Multiattack. The living bog makes one slam attack against each creature in its space.
  • Slam. Melee Weapon Attack: +14 to hit, reach 0 ft., one target. Hit: 24 (4d6 + 10) bludgeoning damage and the target must make a DC 18 Constitution saving throw or become poisoned for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
  • Swampgas (3/day). The living bog expels a 20-foot-radius spherical cloud of choking, noxious gas within 30 feet of itself. These clouds are nonmagical, don’t require concentration, and disperse naturally after one minute, but are otherwise identical to stinking cloud, with a saving throw DC of 18. The living bog itself is immune.
  • Swamplights. The living bog casts dancing lights.
  • Sedentary Slime. A living bog is an enormous, amorphous creature, or thing, that inhabits marshes and wetlands, existing only to feed and grow. It doesn’t like to move, and will find a comfortable spot, near where creatures are likely to pass, and remain in place for as long as prey is plentiful. Some remain stationary for years, the corrosion-resistant bits of their victims’ possessions slowly accumulating beneath their putrid mass.


The living bog will often lie in place for days or weeks at a time, using its Swamplights to lure prey. It is not intelligent enough to distinguish easy prey from difficult, nor to flee if in danger, but it instinctively uses its various abilities to great effect. It will typically use only its slam attack until it loses a quarter of its hit points, and then let loose with everything it has.


A number of small glowing lights begin to bob and weave through the air over the vast swampy pool. As much as 50 feet across, a living bog is normally indistinguishable from the ordinary pools found in any swamp or marsh. When roused, though, it forms appendages that resemble elementals of some kind, rising from the murk as a fetid, shapeless masses of water, muck, and decomposing plants.

Section 15: Copyright Notice

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