Underdark
Monsters found in Underdark
All Monsters (182)
- Aboleth - Ancient race of fish-like amphibians with three eyes and four tentacles
Field Guide - Aergian Amalgamation - A violent creature formed from failed adventurers' souls, resembling four monstrous hands with six tentacle-like appendages
Field Guide - Alabaster Serpent
CC #2 - Amber Creeping Vine - A climbing plant with striking amber flowers that feeds on the brains of living creatures
OSRIC - Ant Lion, Giant - A gigantic predatory beetle about the size of a cow that builds underground tunnel networks with trapdoor ambushes
Field Guide - Ape, White - Albino, herbivorous, gorilla-like apes that live in caves and emerge at night to forage
OSE - Arachnid, Giant Tarantella - Huge, hairy, nocturnal arachnid carnivores with large heads and mandibles and 10 legs
OSE - Aurumvorax - Eight-legged mustelid the size of a medium dog with a thick gold coat
Field Guide, OSRIC - Basilisk - 10' long, serpentine lizards. Unintelligent, but highly magical
OSE, OSRIC - Bat, Ordinary - Common bats that swarm when startled
OSRIC - Bear, Cave - Monstrous bears even larger than grizzly bears
BFRPG, OSRIC - Bee, Giant - Giant bees that live in underground hives with a queen
BFRPG - Beetle, Giant Boring - Giant beetles that eat rotting wood and operate like a hive collective
Field Guide - Beetle, Giant Fire - Huge beetle with glowing red organs that provide illumination
BFRPG, Field Guide - Beetle, Giant Oil - Giant beetle about 3 feet long with eyes that can see in all directions
BFRPG, Field Guide - Black Pudding - Amorphous creature that lives only to eat, scouring underground areas for organic matter
BFRPG, OSE - Black Widow - 6' long, black spiders with a red hourglass pattern on their abdomens
OSE - Blindheim - Yellowish, frog-like humanoids that project twin beams of incredibly bright light from their eyes
OSRIC - Boar, Sewer - Distant relative of the wild boar that lives underground in dungeons or sewers
Field Guide - Boglin - Goblins born with bluish skin who develop magical abilities
Field Guide - Brazen Sphere Imprisoner - The rarest manifestation of brazen spheres, an 8-foot tall sphere that imprisons solitary intruders
Field Guide - Brown Mold - A fungus that feeds on light and warmth, causing cold damage to nearby creatures
Field Guide - Brown Mould - A heat-absorbing fungus that feeds on energy and grows in darkness
OSE-AF, OSRIC - Bulette - Terrifying predator that resembles a gigantic armadillo crossed with a snapping turtle
Field Guide, OSE-AF, OSRIC - Cadaver - A corporeal undead creature resembling a ghoul that subsists by eating the flesh of other undead creatures
Field Guide - Caecilia, Giant - Carnivorous, legless amphibians that resemble giant earthworms with bony skeletons and sharp teeth
BFRPG - Carcass Creeper - A fearsome, subterranean omnivore described as the magical hybrid of a cutworm and a squid
OSRIC - Carrion Crawler - 9' long, 3' high, many-legged, segmented worms with a ring of 2' long tentacles around their mouths
OSE - Caterwaul - Feline predator resembling black panthers walking upright that stalks darkened caves
OSRIC - Cave Bear - Ferocious, 15' tall grizzly bears found in caves and Lost World settings
OSE - Cave Lizard - Lizards that dwell in underground settings with camouflage colouration
OSRIC - Cave Locust, Giant - Pale, cricket-like creatures that live underground, 2 to 4 feet long
BFRPG - Centipede, Giant - Larger versions of normal centipedes, 2 to 3 feet long, fast-moving predatory venomous arthropods
BFRPG, OSE, OSRIC - Cheiropteran - Bat-people of the deep under-dark with bugbear-like bodies and misshapen bat heads
Field Guide - Choker - A vicious little predator that lurks underground, grabbing prey with spiny-padded hands and feet
Field Guide - Cloaker - Almost impossible to distinguish from dark surroundings when resting, with glowing eyes, needle-sharp fangs, and a whip-like tail
Field Guide - Coffer Corpse - Resembles a zombie, a rotting, fetid corpse of the dead left unburied
OSE-AF, OSRIC - Crab, Giant - Large crustaceans averaging 5' in diameter, tolerant of various water conditions
BFRPG - Crypt Dweller - An undead creature improperly buried or placed into a grave that has been desecrated or defiled
Field Guide - Crypt Thing - A cloaked skeleton that guards its lair with teleportation magic
OSRIC - Cyclops - 20' tall humanoids with a single, central eye
OSE, OSRIC - Dark Creeper - Short, spindly humanoids with pale skin who wrap themselves in loose, dark clothing
OSE-AF, OSRIC - Dark Stalker - Leaders of the dark creepers, much taller than their followers
OSRIC - Darkmantle - A cave-dwelling creature that resembles a stalactite and drops onto prey to suffocate them
Field Guide - Darktorch - Undead adventurer wielding a torch of pure darkness, seeking to spread its eternal curse
Field Guide - Deadringer - A rare skeletal undead that rings bells to empower other undead and curse the living
Field Guide - Deep One
OSE-AF - Deep Spore - Knobby leathery globes 2-5 feet in diameter with large eye spots that float in underground realms
Field Guide - Delver - A cross between an enormous centipede and a slug, roughly 15 feet long and 12 feet tall
Field Guide - Dragon, Cave - Solitary, territorial dragons dwelling in the deepest caverns with exceptional echolocation abilities
Field Guide - Draugr - Undead remains of an ancient king, appearing as a skeleton wearing antique plate mail
Field Guide - Drider
OSE-AF - Drow
OSE-AF - Duergar
OSE-AF - Dwarrow - A grim, evil race who are cousins to the dwarves
Field Guide - Ear Worms - Tiny insect larvae found in old wood that burrow through flesh to mature
Field Guide - Elf, Brugh - An elf subspecies that dwells in underground complexes beneath earth mounds known as "Brughs"
Field Guide - Ettin - Large, nocturnal two-headed creatures that live below ground
OSE-AF, OSRIC - Executioner's Hood - A small, weird monster that drops from above to strangle victims
OSRIC - Eye of Terror
OSE-AF - Fire Beetle - 2½' long. Commonly found underground
OSE - Fire Lizard - Giant lizards with tough scaled hide, thought to be an evolutionary dead-end on the dragon family tree
OSRIC - Flail Snail
OSE-AF - Flame Lizard
OSE-AF - Frost Toad
OSE-AF - Fungi, Octopus - A giant fungus that appears similar to wailing morels but unfurls a tentacled appendage to grasp victims
Field Guide - Gas Spore - Strange, non-intelligent fungal creatures that resemble oculus
Field Guide, OSE-AF - Gelatinous Cube - Nearly transparent cube that travels dungeon corridors absorbing carrion, creatures, and trash
BFRPG, OSE, OSRIC - Ghost Shroom - A patch of black mushrooms that behaves as undead, subsisting on dead flesh
Field Guide - Giant Bat - Large carnivorous bat with 15-foot wingspan
BFRPG, OSRIC - Giant Ferret - 3' long ferrets that hunt giant rats in their burrows
OSE - Giant Mutant Frog
OSE-AF - Giant Shrew - Brown-furred, mole-like, insectivores with long snouts. Dwell underground; skilled burrowers.
OSE - Giant SLug - Large boneless creatures that spit acid and burrow through wood and earth
OSE-AF, OSRIC - Giant Tick - Giant invertebrates that dwell in ruins and upper dungeon levels
OSRIC - Giant Weasel - 8' to 9' long, vicious, predatory mammals with rich fur of brown, gold, or white
OSE - Gibbering Mouther - A horrible creature seemingly drawn from a lunatic's nightmares with the fluid body of an amoeba
Field Guide, OSE-AF - Golem, Lead - Ancient construct sacred to the bat-god Camazotz, man-shaped with bat head and wings
Field Guide - Grave Dancer - An undead monster appearing as a macabre figure dressed in brightly-colored but worn and tattered clothing
Field Guide - Grawl - Savage race of subterranean dwelling humanoids with pale gray fur, sharp claws, and panther-like heads
Field Guide - Green Slime - Dripping, green slime that clings to walls and ceilings
OSE, OSRIC - Grey Ooze - Slimy horrors that lurk on stone surfaces or among boulders
OSE, OSRIC - Grick - Large snake-like creature with tentacles that hunts from hiding in shadows
Field Guide - Grimlock - Muscular humanoid with gray skin that is blind but has exceptional senses of smell and hearing
Field Guide, OSRIC - Grue
CC #4 - Gullygug
OSE-AF - Hook Beast
OSE-AF - Hulker
OSE-AF - Hydral
CC #2 - Hydral Statue
CC #2 - Ice Troll - Semi-transparent trolls with bodies that appear chiselled from blue-tinged ice
OSRIC - Infrachameleon
CC #4 - Jelly, Black - Amorphous creatures that live only to eat, inhabiting underground areas
BFRPG - Jelly, Glass - Huge transparent jelly that absorbs carrion and creatures, trapping inorganic material visibly inside its body
BFRPG - Jelly, Gray - Amorphous creatures that live only to eat, scouring underground areas
BFRPG - Jelly, Green - Bright green, wet, and sticky jelly that devours flesh and organic materials on contact
BFRPG - Killer Bee - Giant (1' long) bees of aggressive temperament. Build hives underground.
OSE - Kobold - Small, dog-faced reptilian humanoids
BFRPG, OSE, OSRIC - Krell
OSE-AF - Lantern Moths
CC #4 - Large Spider - Common dungeon and ruin dwelling spiders of various shapes and colours
OSRIC - Living Darkness - A mindless unintelligent subterranean creature that appears as a black mist or cloud of slowly-moving smoke
Field Guide - Lizard, Giant Minotaur - Large ambush predator with horned projections and stone-like coloration
Field Guide - Lizard, Giant Subterranean - Huge lizards with pale yellow or white skin found only in large underground areas
Field Guide - Lizard, Giant Tuatara - Large, heavily built predators with powerful shearing bite
BFRPG - Loadstar - Ball of thin iron spikes that injects fast-growing parasitic embryos
Field Guide - Lurker - Dangerous creatures resembling manta rays that wait in high places to drop on prey
OSRIC - Lurker Above - A subterranean creature resembling a manta ray that swims through the air and drops on prey from ceilings
Field Guide, OSE-AF - Lycanthrope, Werecockroach - A human who can transform into a gigantic cockroach
Field Guide - Mimic - A master of deception that can assume the shape of any object or creature
Field Guide, OSE-AF - Mind Lasher
OSE-AF - Minotaur - Huge bull-headed humanoid monsters
BFRPG, OSE, OSRIC - Mobat - Very large bat found in warm regions with plentiful warm-blooded prey
OSRIC - Moonshiner - A six-legged excessively-muscled hound with an over-sized jaw and a penchant for a stiff drink
Field Guide - Multichromatic Dragon
OSE-AF - Mushroom Men - Intelligent fungal creatures found in subterranean and sylvan environments
Field Guide - Mycelian
OSE-AF - Naga, Spirit - Evil serpentine creatures with human-like heads covered in glossy black scales marked with red patterns
Field Guide - Neanderthal - Squat, powerful, primitive demihumans with ape-like faces
OSE - Nilbog - A goblin infected with nilbogism, surrounded by a weakness in reality that causes chaotic, contrary effects
OSRIC - Norker - Fully subterranean members of the goblin races with tough leathery skin and long protruding fangs
Field Guide - Ochre Jelly - Giant, ochre amoeboids
OSE - Octobat - An intelligent subterranean creature that often works for powerful evil individuals
Field Guide - Oil Beetle - 3' long, burrowing beetles sometimes encountered below ground
OSE - Oil Mites
CC #4 - Otyugh - Large creature with 4 legs, 8-foot diameter body, and 3 tentacles behind its mouth
Field Guide, OSE-AF, OSRIC - Phantom Fungus - Invisible fungal creature that appears as a brown mass with nodules when visible
Field Guide - Piercer - A cone-shaped shelled creature resembling a snail that hunts by dropping from cave ceilings
Field Guide, OSE-AF, OSRIC - Purple Worm - Gigantic subterranean monsters with poisonous stingers
BFRPG, OSE, OSRIC - Pyrolater
CC #4 - Quartz Roper - Rocky creature with living quartz hide that appears as a brownish or smoky grey crystalline statue
OSRIC - Red Slime - An oozing mass that appears to be a red pool, notorious for hiding and surprising victims
Field Guide - Rhagodessa, Giant - Spider-scorpion creature with sticky pedipalps for capturing prey
BFRPG - Rock Bat - A silicate creature that resembles a large, irregular, generally rounded rock with a horn on the bottom of its body
Field Guide - Rock Cricket - 2–3' long, herbivorous, giant crickets that dwell in caverns
OSE - Rock Troll - Underground-dwelling trolls with calcified rock-like exoskin
Field Guide - Roper - A 9-foot tall creature that tapers from 3-4 feet in diameter at the base to 1 foot at the top, weighing 2,200 pounds
Field Guide, OSE-AF, OSRIC - Rust Monster - Strange monster built like a huge turtle with insectoid head and feather-like antennae
BFRPG, OSE, OSRIC - Serpent Men - Vile creatures that once ruled the world and wish to do so again
Field Guide - Shambling Mound - Intelligent plant creatures appearing as piles of rotting vegetation
OSE-AF, OSRIC - Shrieker - Large, semi-mobile fungus that wails loudly when approached or threatened
BFRPG, OSE, OSRIC - Skeleton - Mindless undead created to guard tombs or serve their creator
BFRPG, OSE, OSRIC - Spawn of the Worm
OSE-AF - Spider, Giant Black Widow - Much enlarged version of the ordinary black widow with strong, deadly venom
BFRPG - Spider, Giant Trapdoor - A pony-sized spider that digs deep tunnels with camouflaged trapdoor entrances
Field Guide - Spider, Giant Wolf - Swift hunting spider with natural camouflage, about 3 feet tall and 5 feet long
Field Guide - Spirit Naga - Evil naga with black scales and blood red bands, large misshapen human-like head
OSRIC - Stone Giant - 14' tall humanoids with stone-like, grey skin
OSE - Strix - Grotesque flying heads with slithering tentacles for hair and bat-like wings
Field Guide - Strober
CC #4 - Stunjelly - Translucent creature that appears as a normal section of wall until prey approaches
OSRIC - Stygian Sphere
CC #4 - Subterranean Lizard
OSE-AF - Svirneblin
OSE-AF - Syring - A 9-foot tall, four-legged insect-like creature with a striking resemblance to a spider
Field Guide - Syring Juggernaut - A 24-foot tall syring with 3 thoraxes and scorpion-like tail, covered in white eyes
Field Guide - Tapper - Undead dwarven miners driven by greed, risen from the dead to guard their claims
Field Guide - Thoul - Magical monstrosities that look like hobgoblins (except on close inspection), but combine the powers of ghouls and trolls
OSE - Thulid - Highly intelligent man-like creature with a squid-like visage and four to ten tentacles surrounding a beak-like mouth
Field Guide - Tommyknocker - Mischievous little people that infest mines, causing trouble by stealing and sabotaging operations
Field Guide - Torch Bearer’s Ghost
CC #4 - Trapper - An amorphous ambush predator that lies flat and mimics stone floors
Field Guide, OSE-AF, OSRIC - Trobold - A 3-foot tall magical troll-kobold hybrid with rubbery gnarly limbs, sharp clawed hands, and multiple rows of sharp teeth
Field Guide - Troglodyte - Intelligent, reptilian humanoids with agile hands, long legs, short tails, and spiky combs on their heads and arms
OSE, OSRIC - Troll, Giant Two-Headed - Vicious offspring of trolls and ettins with two heads and regenerative abilities
OSRIC - Underdark Monsters in Basic Fantasy Field Guide Omnibus
- Underdark Monsters in Basic Fantasy Role-Playing Game
- Underdark Monsters in Carcass Crawler Issue 2
- Underdark Monsters in Carcass Crawler Issue 4
- Underdark Monsters in Old-School Essentials Advanced Fantasy Genre Rules
- Underdark Monsters in Old-School Essentials Classic Fantasy
- Underdark Monsters in OSRIC
- Vermen - Medium-sized furred humanoid with a rodent-like head and tail
Field Guide - Vilstrak - Rocky-skinned subterranean humanoids that merge with stone
OSRIC - Violet Fungi - Very large purple mushrooms that resemble wailing morels with flailing branches
Field Guide - Violet Fungi - Plant creature that resembles shriekers, with branches that release rotting spores
OSRIC - Violet Fungus - A purple to gray fungus that resembles a shrieker, attacks with poisonous tentacles
Field Guide, OSE-AF - Worm Man - Humanoid worms that live deep underground, about 7 feet long with two arms and excellent peripheral vision
Field Guide - Xorn - An embodiment of the element of Earth that glides through stone
Field Guide, OSE-AF, OSRIC - Yellow Mold - A poisonous fungus that releases deadly spores when disturbed
Field Guide - Yellow Mold - Poisonous fungus that releases deadly spores when disturbed
BFRPG - Yellow Mould - Deadly fungus that covers walls, ceilings, and other surfaces
OSE, OSRIC