Bog Crawler

Gargantuan aberration, unaligned

Armor Class 18 (natural armor)
Hit Points 279 (18d20 + 90)
Speed 40 ft., swim 40 ft.

26 (+8) 10 (+0) 21 (+5) 3 (–4) 11 (+0) 5 (–3)

Saving Throws Con +10, Wis +5
Damage Immunities acid, poison
Condition Immunities charmed, frightened, paralyzed, poisoned
Senses darkvision 120 ft., passive Perception 10
Challenge 15 (13,000 XP)
Proficiency Bonus +5


  • Amphibious. The bog crawler can breathe air and water.
  • Slimy Movement. The bog crawler ignores difficult terrain, and magical effects can’t reduce its speed or cause it to be restrained. It can spend 5 feet of movement to escape from nonmagical restraints or being grappled.


  • Multiattack. The bog crawler makes two tentacle attacks, or one tentacle attack and one bite or swallow.
  • Bite. Melee Weapon Attack: +13 to hit, reach 5 ft., one creature. Hit: 34 (4d12 + 8) piercing damage, and the target is grappled (escape DC 21). Until this grapple ends, the target is restrained, and the bog crawler can’t bite another target.
  • Tentacle. Melee Weapon Attack: +13 to hit, reach 20 ft., one creature. Hit: 26 (4d8 + 8) bludgeoning damage, and the target is grappled (escape DC 21). Until the grapple ends, the target is restrained. The bog crawler has six tentacles, each of which can grapple one target.
  • Swallow. The bog crawler makes one bite attack against a Huge or smaller creature it holds grappled with its bite. If the attack hits, the target takes the bite’s damage, the grapple ends, and the target is swallowed. While swallowed, a creature is blinded and restrained, has total cover against anything originating outside the bog crawler, and takes 36 (8d8) acid damage at the start of each of the bog crawler’s turns. If the bog crawler takes 30 damage or more on a single turn from a creature inside it, the bog crawler must succeed on a DC 21 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in spaces within 10 feet of the bog crawler. If the bog crawler dies, a swallowed creature is no longer restrained by it and can escape the corpse by using 15 ft. of movement, exiting prone.


Hulking Terrors. Fleshy masses of a vaguely amphibian shape, these monstrosities wriggle out from deep hibernation in chaotic cycles, baffling the few naturalists who dare study them. The crawlers emerge ravenous, destroying everything in their path in search of food.

Bizarre Horrors. Disgusting masses caked with mud and slime, the bog crawler’s brown skin is covered in warts. Its face is somewhat frog-like, with a large mouth and multiple rows of sharp teeth. Its tail is a writhing mass of small tentacles that scuttle along the ground, propelling the creature on land and stabilizing it in water. Six large tentacles jut from the mass of its body, three on each flank, and are long and strong enough to attack nearby creatures and structures.

Famished Hunters. These beasts’ primary motivation is hunger. They eat any flesh, starting with wildlife, moving on to livestock, and then feasting on any community they encounter. Much like a snake, their jaws are connected by a ligament and muscle network, allowing them to unhinge and swallow enormous creatures.

Inexplicable Retreat. While most bog crawlers spend a great time feeding, others retreat early, their hunger seemingly slaked. If a reason for these premature hibernations could be found, untold carnage might be avoided.

  • DC 10 Intelligence (History): Bog crawlers are massive creatures capable of great destruction and carnage. They worm their way out of ancient burrows to feed after hundreds of years of hibernation.
  • DC 15 Intelligence (Arcana): Bog crawlers are immune to acid and poison. They can swallow creatures almost as large as they are, topple towers and strongholds, can’t be stopped by charm or paralysis, and are immune to fear.
  • DC 20 Intelligence (Nature): While a bog crawler’s ability to swallow creatures is their greatest danger, they can use their main tentacles to grab and hold prey.
Section 15: Copyright Notice

Grim Hollow: The Monster Grimoire © 2021, Ghostfire Gaming Pty Ltd. Author: Shawn Merwin

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