Underground Monsters
in Basic Fantasy Field Guide Omnibus
66 monsters
- Aergian Amalgamation - A violent creature formed from failed adventurers' souls, resembling four monstrous hands with six tentacle-like appendages
- Ant Lion, Giant - A gigantic predatory beetle about the size of a cow that builds underground tunnel networks with trapdoor ambushes
- Aurumvorax - Eight-legged mustelid the size of a medium dog with a thick gold coat
- Beetle, Giant Boring - Giant beetles that eat rotting wood and operate like a hive collective
- Beetle, Giant Fire - Huge beetle with glowing red organs that provide illumination
- Beetle, Giant Oil - Giant beetle about 3 feet long with eyes that can see in all directions
- Boar, Sewer - Distant relative of the wild boar that lives underground in dungeons or sewers
- Boglin - Goblins born with bluish skin who develop magical abilities
- Brazen Sphere Imprisoner - The rarest manifestation of brazen spheres, an 8-foot tall sphere that imprisons solitary intruders
- Brown Mold - A fungus that feeds on light and warmth, causing cold damage to nearby creatures
- Bulette - Terrifying predator that resembles a gigantic armadillo crossed with a snapping turtle
- Cadaver - A corporeal undead creature resembling a ghoul that subsists by eating the flesh of other undead creatures
- Choker - A vicious little predator that lurks underground, grabbing prey with spiny-padded hands and feet
- Cloaker - Almost impossible to distinguish from dark surroundings when resting, with glowing eyes, needle-sharp fangs, and a whip-like tail
- Crypt Dweller - An undead creature improperly buried or placed into a grave that has been desecrated or defiled
- Darkmantle - A cave-dwelling creature that resembles a stalactite and drops onto prey to suffocate them
- Darktorch - Undead adventurer wielding a torch of pure darkness, seeking to spread its eternal curse
- Deadringer - A rare skeletal undead that rings bells to empower other undead and curse the living
- Delver - A cross between an enormous centipede and a slug, roughly 15 feet long and 12 feet tall
- Draugr - Undead remains of an ancient king, appearing as a skeleton wearing antique plate mail
- Dwarrow - A grim, evil race who are cousins to the dwarves
- Ear Worms - Tiny insect larvae found in old wood that burrow through flesh to mature
- Elf, Brugh - An elf subspecies that dwells in underground complexes beneath earth mounds known as "Brughs"
- Fungi, Octopus - A giant fungus that appears similar to wailing morels but unfurls a tentacled appendage to grasp victims
- Gas Spore - Strange, non-intelligent fungal creatures that resemble oculus
- Ghost Shroom - A patch of black mushrooms that behaves as undead, subsisting on dead flesh
- Gibbering Mouther - A horrible creature seemingly drawn from a lunatic's nightmares with the fluid body of an amoeba
- Grave Dancer - An undead monster appearing as a macabre figure dressed in brightly-colored but worn and tattered clothing
- Grawl - Savage race of subterranean dwelling humanoids with pale gray fur, sharp claws, and panther-like heads
- Grick - Large snake-like creature with tentacles that hunts from hiding in shadows
- Grimlock - Muscular humanoid with gray skin that is blind but has exceptional senses of smell and hearing
- Living Darkness - A mindless unintelligent subterranean creature that appears as a black mist or cloud of slowly-moving smoke
- Lizard, Giant Minotaur - Large ambush predator with horned projections and stone-like coloration
- Lizard, Giant Subterranean - Huge lizards with pale yellow or white skin found only in large underground areas
- Loadstar - Ball of thin iron spikes that injects fast-growing parasitic embryos
- Lurker Above - A subterranean creature resembling a manta ray that swims through the air and drops on prey from ceilings
- Lycanthrope, Werecockroach - A human who can transform into a gigantic cockroach
- Mimic - A master of deception that can assume the shape of any object or creature
- Moonshiner - A six-legged excessively-muscled hound with an over-sized jaw and a penchant for a stiff drink
- Mushroom Men - Intelligent fungal creatures found in subterranean and sylvan environments
- Naga, Spirit - Evil serpentine creatures with human-like heads covered in glossy black scales marked with red patterns
- Norker - Fully subterranean members of the goblin races with tough leathery skin and long protruding fangs
- Octobat - An intelligent subterranean creature that often works for powerful evil individuals
- Otyugh - Large creature with 4 legs, 8-foot diameter body, and 3 tentacles behind its mouth
- Phantom Fungus - Invisible fungal creature that appears as a brown mass with nodules when visible
- Piercer - A cone-shaped shelled creature resembling a snail that hunts by dropping from cave ceilings
- Red Slime - An oozing mass that appears to be a red pool, notorious for hiding and surprising victims
- Rock Bat - A silicate creature that resembles a large, irregular, generally rounded rock with a horn on the bottom of its body
- Rock Troll - Underground-dwelling trolls with calcified rock-like exoskin
- 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
- Serpent Men - Vile creatures that once ruled the world and wish to do so again
- Spider, Giant Trapdoor - A pony-sized spider that digs deep tunnels with camouflaged trapdoor entrances
- Spider, Giant Wolf - Swift hunting spider with natural camouflage, about 3 feet tall and 5 feet long
- Strix - Grotesque flying heads with slithering tentacles for hair and bat-like wings
- Syring - A 9-foot tall, four-legged insect-like creature with a striking resemblance to a spider
- Syring Juggernaut - A 24-foot tall syring with 3 thoraxes and scorpion-like tail, covered in white eyes
- Tapper - Undead dwarven miners driven by greed, risen from the dead to guard their claims
- Thulid - Highly intelligent man-like creature with a squid-like visage and four to ten tentacles surrounding a beak-like mouth
- Tommyknocker - Mischievous little people that infest mines, causing trouble by stealing and sabotaging operations
- Trapper - An amorphous ambush predator that lies flat and mimics stone floors
- Trobold - A 3-foot tall magical troll-kobold hybrid with rubbery gnarly limbs, sharp clawed hands, and multiple rows of sharp teeth
- Vermen - Medium-sized furred humanoid with a rodent-like head and tail
- Violet Fungi - Very large purple mushrooms that resemble wailing morels with flailing branches
- Violet Fungus - A purple to gray fungus that resembles a shrieker, attacks with poisonous tentacles
- Xorn - An embodiment of the element of Earth that glides through stone
- Yellow Mold - A poisonous fungus that releases deadly spores when disturbed