Underworld Wilderness Dressing: Living

d12
1. Ceiling rats scramble about overhead, occasionally dropping into hoods, backpacks, etc.
2. Gas-bag jellies harmlessly bobbling around zapping insects with electrical discharge
3. Dungeon magpies: highly intelligent but wits short-circuited by shiny objects
4. Disturbingly large pillbugs creep out of unseen hidey-holes to haul away the recent dead
5. Shell-less giant tortoises, extremely poisonous secretions made the shell redundant
6. Juggernaut cockroaches, non-aggressive, but natural defenses include reeking offensively and mimicking voices of nearby sentient creatures
7. Impoverished horde of dungeon pixies begging for alms, generous donors receive impromptu musical performance with astonishing production values
8. Research team taking various readings for sorcerer/scientist, interested in PC answers to a short survey
9. Giant hermit crabs disguised as huge boulders
10. Wall-adhered polyps of unknown origin: ooze a bit, occasionally whine
11. Red cavern weed: thermosynthetic, cluster around natural (and otherwise) heat sources, fronds wave around as if in stiff breeze
12. Troll head (quite alive) sticking out from underneath rubble of collapsed column

Spanning the Underworld Chasm

d12
1. Giant arcing termite nest complete with miniature ecosystem (fungi, lichens, giant aphids, micro-puddings, etc.)
2. 3-rope bridge hastily contrived and abandoned by adventuring party now dead to a man
3. Sturdy bridge crafted from single dried stalk of titanic fungus
4. Gondola suspended on steel cables operated by winch and pulley system, currently occupied by crazed cannibalistic hermit
5. Mechanical toll-drawbridge/mini-fortress full of murder holes, manned by exceedingly well-armed deep dwarf clan
6. Trolls just use the catapults on either side
7. Rope guided para-sailing gear & magical wind generator stored inside nigh-impregnable lockers
8. There's this semi-friendly giant with an excellent throwing arm
9. Fossilized mythic-sized spiderweb left over from the eldest days
10. Rough bridge of volcanic rock: composed of self-sacrificed bodies of countless lava-men
11. Shimmering spectral arch made of ever-howling ghosts and soul-matter fused and shaped by a wicked sorcerer thinking only of his own convenience
12. Coils of a primordial dragon petrified by the powers of its victorious demigod rival, stairs and footpaths worn in after centuries of use, said to predate the chasm itself

What's up at the Underworld Chaos Temple?

d12
1. Closed for repairs after raid by Deep Dwarf Agnostic Jihad
2. Secret unholy ritual in progress, no admittance, heavy guard
3. Open worship featuring mind-bending oratory of chaos, not particularly uplifting
4. Emergency sacrifice required, heavily armed squads hunt for itinerant sentients
5. Partial corporeal manifestation of deity: high priestess expected to be consumed following string of recent screw ups
6. Annual opening of the gates to hellish nightmare plane of unspeakable deity for import/export
7. Implosion imminent! licence revoked by deity after heretical activities by clergy, temple to be destroyed utterly via singularity
8. Infidel attack/looting in progress
9. Temple-wide mandatory fortnight of fasting and meditation
10. War priest seminary training underway: mace practice, human sacrifice class using dummies
11. Desperate times: starving priests, denied powers by disapproving divinity, beg for food and mournfully cry out for salvation
12. Observance of Underworld holy day (see Underworld Festivals and Holy Days)

Giant Worms of the Underworld

d12
1. Earthquakers: colossal entities, probably immortal, tamper with tectonic plates for inscrutable purposes
2. Magma worms: black plated, incredibly dense, believe selves to be first terrestrial intelligence, gently condescending to newer sentients on the scene
3. Dwarf-eaters: bred by ancient sorcerer w/anti-dwarf bias, prey upon any humanoid but go out of their way for dwarf-flesh, heads like hammerhead sharks bristling w/waving sensillae
4. Worm folk: roughly man-sized when reared up on caterpillar-like sets of hind legs, frail and fragile, mentally enslave more dexterous creatures to do their dirty work
5. Emperor worm: singular being venerated by all thinking worms, who are subject to its mental orders at whim
6. Wind-vomiting worms: quasi-divine leviathans provide the Underworld w/its peculiar weather phenomena
7. Artworms: creators of mad, surreal, non-representational sculpture, sojourn through the solid earth in search of great caverns in need of mind-bending decoration
8. Gold-eaters: miners follow them to mother lodes, thieves follow them to unprotected treasuries, will only stop eating if slain
9. Army worms: appreciable communal intellect, telepathic, martial society bent on conquest for its own sake
10. Servitor worms: bred by dwarfs for mining, ore processing, generally well-behaved, occasionally go rogue at the behest of the Emperor worm
11. Lore-keeper worms: observers of the Underworld, encode their findings in great bas reliefs in their vast library caves
12. Arrow worms: bred by subterraneans as missile weapons that start eating targets upon impact

Weird Bats of the Underworld

d12
1. Sucker bats: the lamprey eel of the Underworld, tolerated by large creatures
2. Man-face bats: normal bats w/maned and bearded human-like heads
3. Vulture bats: huge carrion eaters, viciously defend carcasses
4. Wound seekers: like ravens, attracted to sites of recent battle
5. Stench bats: emit defensive inky cloud of toxic gas when disturbed
6. Large mouth bats: huge filter feeders swoop around dining on aero-prawns and the like
7. Moth bats: mindlessly attracted to light sources, often snuffing out torches
8. Singing bats: fly in complex formations, create mesmerizing harmonies
9. Hover bats: four-winged creatures buzz around like remote control helicopters
10. Assassin bats: picks victim and begins campaign of single attacks, inflicting death by 1000 cuts
11. Spider bats: lost ability to fly, instead scuttle along walls and ceilings, hunting in packs
12. Fluttering things: bat-wings with no bodies, a mystery of the Underworld

Underworld Currency

d12
1. Lead coins bearing stamped insignia of underworld overlord
2. Shiny, tumble-polished purple rocks in three sizes
3. Dungeon fairy dust: by weight, kept in silk bags
4. Dragon scales or varying color/quality
5. Heads/skulls, by size, degree of freshness
6. Live snails, by shell color and complexity
7. Ingested globule: value encoded in RNA
8. Rare and precious gas exchange: money balloons
9. Tally bones
10. Intricately embossed tin notes: represent chunks of unrefined ores
11. Sealed ceramic pots containing various denominations of mucks, mires, bog-waters, sloughs and ichors
12. Souls trapped in crystal matrix

Underworld Entertainments

d12
1. Headless dance troupe under psychic control of mind-eater choreographer
2. Recitation of ghastly epic poem by obese ogre noted for exceedingly well-moderated vocal tones
3. Subterranean ape acrobats directed with roared commands by massive and unmoving bull ape: prefer to be paid in food
4. Subhuman chief's bi-annual abomination hunt: 100's of stone implement equipped contestants swarm about in frenzy, hoping to win substantial reward
5. After eleven months of dour taciturnity grey dwarfs celebrate month-long Festival of Mayhem
6. Spellbinding oratory available weekly at regional Temples of Chaos
7. Slug-man dramatists perform days-long tragedies w/elaborate SPFX provided by company wizard
8. Subhumans jam nightly on variety of stone & bone rhythm instruments while deranged on fermented ogre saliva brew
9. Vampire entrepreneur leads wagon-train zoo, charges modest fee for subterraneans to ogle such semi-unknown surface creatures as unicorns, ducks, halflings
10. Oral storytelling time w/the eons-addled dragon who never shuts up: 1 in 6 chance of uttering useful information, 1 in 20 audience members absent-mindedly devoured
11. Disembodied head chorus, witch doctor conductor: not really meant for human ears, an acquired taste
12. Spectacular public executions, jazzed up for maximum entertainment value: ex. live cave wall "action painting" using condemned prisoners and trebuchet 

Effects of Long-term Exposure to the Underworld

d12
1. Paranoiac hyper-vigilance: reduced sleep requirement/accelerated aging process, shifty eyes, constant perspiration
2. Rapid onset full-body hair loss
3. Total color blindness: visual acuity increased by several megapixels
4. Sallow, sickly appearance, unhealthy anti-glow: reduced charisma
5. Absorption of trace airborne elements triggers coarsening of skin: as leather armor, temporarily painful w/dexterity reduction
6. Olfactory enhancement: picking up the subtleties once ignored, chance of surprise reduced, negated by exposure to fresh air
7. Cave depression: emotional responses muted, adrenalin tolerance through the roof, enhanced resistance to fear, panic
8. Ration starvation: vitamins/minerals missing from feed, weight loss, bad breath, immune system compromised (saving throw penalty)
9. Low light vision enhanced, negated by re-acclimation to full daylight
10. Dungeon pragmatism: atrophy permanently erodes empathy, compassion, regard for sanctity of life
11. Systemic fungal infection: increases strength and constitution, occludes thought process
12. Total acclimation: underground environment seems like home, surface life just an increasingly vague memory

Why is there an Underworld?

d12
1. Earth hollowed by extinct giant ants during paleogean Age of Giant Insects
2. Life began in crucible of chaos at center of the earth, only breaching the surface after millions of years in the dark oceans below
3. Groundwork laid by primeval visitation of planet-eating cosmic worms
4. Aboriginal population of mole-men warped into surface races by renegade god
5. Surface evacuated by ancient ones after their twisted sorcery caused the atmosphere to catch fire for 1000 years
6. Planet strip-mined by aliens, totally depleted of element vital to interstellar travel, abandoned
7. Because of a lie the elf fathers told the first dwarf
8. The evil gods imprisoned at the earth's core call out to be freed, their children delve ever downward
9. Fossilized circulatory system of the dead earth god, upon whose corpse we all feast
10. Down below where the goblins and kobolds dwell the god of retribution fuels his spirit-powered engines of anguish with wicked souls
11. Provision of First God War armistice created a permanent division between children of light and darkness, since nullified by renewed hostilities
12. Underground realms left over from first major revision of creation when mountains rained from the sky to forever bury failed experiments

More Wonders of the Underworld

d12
1. The Abyssal Caldera: sight of multiplanar collision and consequent reality breakdown
2. Great Migration of the Cave Worms: annual event marked by festivals and strange observances
3. Non-Euclidean complex of the multi-dimensional ones
4. Niagara-size waterfall that goes up
5. Cave-sepulchre of dead gods: super-powerful agents of divine decomposition pose chief threat 
6. Sculpted halls of the art-beetles (extinct): baroque alien aesthetic mildly mind-bending
7. Mountain of bones, personal collection of the death god
 8. The Grand Chasm: staggeringly vast, spanned only by the Gondola of Peril
9. Mecca of the giants: near-continual stream of giant pilgrims
10. Ruined war-demon factory and test arena: access forbidden by sentry-tribe of subhumans
11. Hanging garden of slimes, puddings, jellies and ooze
12. Life-size statue of incomprehensible god Thloo-huloo exposed by tidal cycle of the Lightless Sea

Weird Underworld Locales

d12
1. The Invisible City
2. Fungus Island on the Sea of Protoplasm
3. The Halls of Tedium (devoid of both monsters and treasure)
4. Divine Singularity (The Swollen God has gone supernova and collapsed)
5. Worm land: ruled by the immortal Lord Fluke
6. Pocket solar system in 0-G spherical cavern
7. The University of Madness
8. Time-slip River: upstream = back in time and vice versa
9. Dissolute Sea: entropic demi-matter, adamant-hulled vessel required
10. Hidden Retreat of the Blind Cave Philosophers: perpetually debating the laws of chaos
11. Spirit cauldron: boiling over with spiritual remnants and fragmented files
12. Fertile chasm: seething chaos-fueled engine of creation continuously spews forth novel life forms

Underworld Transport and Hauling

d12
1. Colossal centipede: operated by sub-human* masters of arthropod husbandry, moves like clockwork between feeding stations (cargo only)
2. All-terrain beetles: up to 4 riders, operated by bio-joystick in thorax
3. Snail-driven sledges of the neutral slug-folk: cargo only, insured, reliable, extremely slow
4. The Lava Schooner
5. Paleogean network of suction tubes: 25% chance of disastrous malfunction/use
6. Flying polyp: enterprising sorcerer makes slave entity available for speedy deliveries (living cargo must submit to temporary encystment), fees exorbitant in the extreme
7. Sarcophagus-shaped transmat booths: relics of a lost civilization, touching glyphs on the inside dictates destination
8. Stone-wheeled land barge powered by pedalling galley apes
9. Ogre-driven rickshaws
10. Train of giant ants: queen deploys her forces in exchange for surface delicacies/magic
11. Underworld Excursion Vehicle (UEV): life's work of underworld-obsessed sorcerer/scientist, provides protection from attacks/elements, array of defensive weaponry (e. g. fireball turret), bio-engine fueled by concentrated food pellets
12.Were-ponies

*Subterranean human: the hairless, chalk-white skinned men native to the underworld

Commonly Abused Underworld Intoxicants

d12
1. Dried bulb of the devil's lily: taken orally eliminates need to sleep for 2d4 days
2. Cerebrospinal fluid of the mind-bat: imparts random knowledge following short pleasurable coma
3. Black mold spores: snorted for hours-long laughing jags, long term users identifiable by tell-tale nasal staining
4. Extract of dragon bile: mildly impaired users able to go with out food for weeks
5. Skin secretions of the blind cave frog: diluted with brandy for an interesting buzz
6. Deep dwarf bracer: served sizzling hot, caustic black syrup heals wounds and renders the drinker even more dour and taciturn
7. Polychromatic fungi: mild hallucinogen, enables user to see in the dark
8. Hydra's tears: renders subject unconscious for 24 hours, during which they are treated to extremely enjoyable dreams
9. Gray cheese: overwhelms the pleasure centers for 10 minutes, then turns skin stone-gray and deadens emotions (cure: more gray cheese)
10. Extra virgin toadstool oil:  taken sublingually, increases sensory awareness
11. War juice: tincture of white ape adrenal fluids and alcohol, induces battle frenzy/heart attack
12. Liquor of fermented ogre saliva: full blown delirium

Benevolent Parasites of the Underworld

d12
1. Cerebral worm: increases intellect, enhances cowardice
2. Detox Tick: palm-sized chigger secretes ichor that nullifies pathogens and poisons
3. Digester ooze: enters stomach, enables host to extract nutrients from most matter
4. Spine dweller: eel-like amphibian incises back, nestles along vertebrae, electrical discharge enhances host's agility
5. Blood swarm: tiny flying arthropods feed upon all gory remnants of melee, cleaning arms and armor
6. Interpreter mite: introduced into ear canal, instantly translates most languages
7. Giant heart fluke: burrows into chest, settles around the heart, produces surges of adrenalin to protect host
8. Pit fleas: saliva blocks pain receptors
9. Love Fungus: grows internally, releases pheromones to attract mates for host, increases personal charm
10. Alien virus: alters host's DNA to produce functional wings, increases caloric requirements ten fold
11. Lung spores: allows respiration in hostile atmospheres/underwater
12. Rockhide: bacterial infection causes skin to harden into armor plates

More Weird Pools

d12
1. The sacred pool of the cave beetle god: surrounded by millions of the tiny zealots in droning prayer
2. The Black Soup of Life: coughs up random embryonic magical beasts
3. The cloning pool: any living thing touching the pool is perfectly cloned in 24 hours *
4. Purple baptismal pond of indelible staining
5. Pool of cold liquid gold: assumes normal state when exposed to sunlight
6. Booze pool: run-off from the deep dwarf distillery
7. Monster oasis: temporary detente between otherwise natural enemies, adventurers not included
8. Translucent predatory protoplasm doing best impression of a pool
9. The pool of growth: any being or object fully immersed permanently doubles in size
10. "Bottomless" pool: trans-dimensional portal
11. The waters of enlightenment: drinking imparts 1d6 minutes of god-like intelligence followed by recuperative coma lasting 1d6 hours
12. Hot Tub of the Gods

* Naturally, the clone will not stop until it has killed and replaced the original

Wandering Underworld Deities

d12
1. Partial corporeal manifestation of Een the All-knowing: broadcasts blinding white light made of information, all present must save or pass out from involuntary download
2. Ytaan the god of discourse: a 12 ft. tall golden man in dapper toga spoiling for debate
3. Grushakh the invisible man-ape demigod: bad ass result of an unholy union between a mighty chief and Kruchtaki the simian goddess of stealth
4. The thousand-winged, innumerably taloned messenger god Urootha on a delivery
5. The Scrutinizing Gaze of Ga: a giant countenance takes shape on a wall, floor, ceiling, rock, etc. and stares intently at those nearby
6. Ssisashi, god of snakes: temporarily occupied with digesting C'chihi the rat god whose still-struggling outline protrudes from Ssisashi's inert coils
7. The Roach Queen: scouting for site of next Holy Infestation
8. Blishnu the Serene: on levitating tour of the underworld, fires bolts of enlightenment from his eye stalks
9. The Lords of the Worm Dance: wave and gyrate in ecstatic ritual, emit rhythmic cacophony that beckons all worms to join in, oblivious to everything but their strange musical pursuits
10. Kurgah the Underworld Excavator: blasts new passages and chambers into the living stone
11. Blaskatal the fire god: investigates the world in the form of charming beggar girl with flaming eyes, undecided on issue of triggering fiery apocalypse
12. Clakatan, Herald of the All-destroyer: a living thunderbolt bellowing out the good news of impending doom to all and sundry

Underworld Hunting and Foraging Success Table

d12
1. 2d6 delicious bats
2. 2d4 plump and juicy rats
3. Large sack full of giant insect larvae
4. Bushel of nutritious lichen
5. A dozen giant lizard eggs
6. Small sack full of edible lizards
7. 1d3 giant rock snails
8. 2d4 cave cephalopods
9. 2d20 giant spider hatchlings
10. Several days worth of life-sustaining pool algae
11. 1d6 blind cave fish
12. Several handfuls of glutinous fungi

Note: assumes presence of native guide or trained Underworld Ranger

Underworld River Vessels

d12
1. Ogre-powered pole barge laden with surface loot
2. Fishing boat w/ giant water beetles trained to retrieve prey
3. Casino boat protected by treaties, neutral ground for all factions, run by extremely dangerous vampire
4. Oil rig-style facility: refines river-bottom sludge into orc chow
5. Algae harvesting skimmers crewed by carapace men
6. Floating temple to the river god: aggressively seeks contributions, filled with zealot-marines
7. Haunted trireme on eternal oddysey: morose spirits of famous heroes of the past
8. Pleisiosaur-riding river knights, love to joust among themselves
9. Giant squid-propelled speed boat pirates
10. Adjustable bridge boat operated by wealthy troll clan
11. Lost and demoralized viking types searching for open sea
12. Reptile men atop giant turtle amphibious assault vessel, shell modified with battlements, arrow slits, tail ramp

Also: The Halfling's Codpiece (dinghy): abandoned

Underworld Cash Crops

d12
1. Ghoulsbane: repels minor undead when smoked profusely, highly addictive
2. Potted Shrieker: lair security device, bred to discern strangers
3. Optic Flora: microscopic plants grow on optic nerve, grants infravision
4. Iron nettles: barbed armor, anti-monster fencing
5. Exploding pods: impact sensitive, launches hail of seed-shrapnel
6. Death spores: airborne poison harvested from giant toadstools
7. Thermolichen: produces berry-like protrusion that when crushed emits heat
8. Levitating fungi: tethered to large objects/loads for transportation
9. Breadcaps: nutritionally complete fungus, deadly poison unless processed
10. Stenchmold: repels reptiles, dinosaurs and dragons, attracts oozes
11. Retchwort: first use: neutralizes most toxins, second use: lethal
12. A rich panoply of psychoactive molds, spores and fungi, carefully bred for effects ranging from the subtlest mood elevation to the most harrowing mind bending delirium (widespread use among kobolds suspected)

Underworld Afflictions

d12
1. Dungeon Itch: mind-bending full body itch, spell casting impossible
2. Mail Rot: starts as obscene stench under armor, advances until tissues slough off
3. Cavern Fever: mounting compulsion to return to surface
4. Ration Starvation: depleted of vital nutrients, weakens, looks terrible
5. Medusa's Blight: skin slowly hardens, hampering movement
6. Troll Flesh: develops green seeping pustules
7. Grave foot: hobbles rapidly, untreated feet blacken and fall off
8. Hill Giant's Hiccups: irrepressible, unpredictable, very loud
9. Berserk's Bane: fever induces spontaneous battle rages + incessant sweating & crazy affect
10. Deep dysentery: explosive onset, severe dehydration, must drain every wineskin to stave off death
11. Tomb Robber's Lung: wracking cough, sensitivity to torch smoke
12. Delver's Blues: turns blue, dies (rapid onset, highly contagious, draconian measures required to halt outbreak)