GHULUKUROS, War-God of the Science Fungoids

Number Appearing: Unique
Size: Approximately 20ft. tall
Armor: Hide like elephant leather, only damaged by enchanted weapons, immune to most spells (anti-magic miasma)
Resilience: Able to absorb as much damage as any 3 giants, regenerates
Intelligence: A genius when it comes to fighting, less so as regards all other subjects
Communication: Emits piercing war-cry only but in many subtle nuances
Disposition: Grim determination
Violence: Enchanted Glaive of Dismemberment able to slice a dragon in half in a single blow, noted for sending limbs flying hither and yon, also lashes out with mighty tentacles if faced with multiple foes
Enemies: Chaos godlings of the Underworld
Aims: Eradicate any who might threaten the interests of the Science Fungoid civilization
Peculiarities: 

• Emits magic-dampening miasma, enveloping Ghulukuros in a 120' diameter cloud that makes breathing difficult, dulls the senses, fogs the mind and causes an irresistible fear in all but the most valiant lesser beings, spells cannot be cast within cloud
• Not actually a god, just has good PR
• One of the earliest and most successful subjects of the Science Fungoids' selective breeding program, created in response to perpetual threat of super-potent Chaos godlings
• Lies inert in nutritive loam-filled sarcophagus, attended by pseudo-priesthood of bio-technicians, jostled back into active duty at need via enormous device similar to defibrillator
• Regeneration defies most conventional (and outré) violence, but vulnerable to powerful digestive enzymes such as those produced by black puddings and other oozes, a closely guarded secret

Treasure: The Glaive of Dismemberment, laden with eldritch martial energies, while unusable by human size creatures, could capture a fortune from the right giant-size buyer

SCIENCE FUNGOIDS

Number Appearing: Small research groups: 2-8, population centers: 40-400
Size: 3-4 feet tall
Armor: Spongy exterior equivalent to leather
Resilience: As 3 human warriors, tenacious regeneration, extremely difficult to destroy permanently, resistant to magic
Intelligence: Human average but face intellectual challenges with inhuman determination unhampered by ethical considerations of any kind
Communication: Tiny voices like bursting bubbles, release clouds of interpreter spores that if inhaled allow permanent comprehension
Disposition: Charming, friendly, generous, overflow with manic joy, emit near-constant peals of high-pitched tittering
Violence: Generally left to humanoid bodyguards, otherwise by weapon
Enemies: Official policy of neutrality, big secret plans for everyone
Aims: Current overriding concern: learning everything there is to know about human(oid) physiology/psychology with a special emphasis on surface beings
Peculiarities:

• Formerly referred to themselves as Wise Gardening Fungoids, spent all energies on creating new and interesting fungal topiary until contact with the blind antler men and their space-born learning triggered a cultural revolution. Unlike the indifferent antler men, the Fungoids set themselves to mastery of the cosmos.
• Specialize in the development and propagation of a wide variety of medicinal, psychoactive, mutagenic, and frequently lethal fungal strains and eagerly test these innovations on human subjects willing to sign a waiver. Additional tests conducted on captive clone populations well out of public view.
• Often freely distribute weaponized puffballs (see below) and spore-laden caps that are known to produce currently unpredictable mutations to adventurers for further field testing if recipient agrees to record effects and return with data
• Underworld ecology now considered well-understood, interest has moved on to the surface world, specifically humanity, marked by the recent opening of the Fungoid Institute of Human Sciences, a magnificent facility on the shores of the Black Ooze River
• Unimpressed with Chaos godlings as a rule, but deal prudently with these beings and their minions 
• Boast the Underworld's only true air force (usable in chambers of sufficient size), composed of living dirigibles, gas bag organisms manipulated and permanently enslaved by allied sorcerers

Treasure: Generally carry enough ready cash in a wide variety of Underworld currencies to grease the wheels of diplomacy, sacks of experimental fungi as noted above

Sample Experimental Fungi  (for OD&D/Swords & Wizardry/that kind of thing):
The (exceedingly grim) anti-personnel puffball grenade
These roughly fist size fungal spheroids burst when met with any sufficient force (such as hitting the ground after a toss) and project a cloud of spores in a 10' radius. Human or human-like creatures exposed to this cloud must make a saving throw or roll 1d6. On a roll 1-4, consult the random result table below. On a roll of 5-6 the victim swells into a giant puffball and explodes the next round, throwing off a 20' cloud of spores. Any within this radius must roll for their lives as above.
Random result table
d4
1. Sudden fungal bloom from within body (perish with maximum unpleasantness in 2 rounds unless magically cured)
2. Funganthropy: victim's form copied (very imperfectly) and replaced by fungal tissue, transformation complete in 1 turn, insane rampage of random violence commences shortly thereafter, hit points doubled due to fungal resilience
3. Victim rooted to the spot by fungal tendrils from legs, fuse completely into immobile stalk in 1 turn, head broadens into cap shape, its all over
4. Puffball fungi begin to grow at alarming rate from every inch of victim's skin, dexterity compromised by -1d6, charisma rendered null and void. Can be carefully shaved off to relatively decent effect, but process must be performed at least thrice daily to mitigate otherwise appalling hideousness and clear and present danger to companions.

PSYCHEPHAGE

Number Appearing: They hunt alone
Size: Roughly human size
Armor: Partially composed of space fungus, easy to strike, difficult to harm
Resilience: As per 4 human warriors, physical weapons inflict only half normal damage
Intelligence: Insect-like
Communication: None as such, but uncanny mimicry ability, can reproduce speech patterns of any previously digested intelligence
Disposition: Cosmic/stupid indifference to everything but the next meal
Violence: Jams hollow proboscis into skull/brain of victim, sucks it out with startling speed, rends w/claws as necessary
Enemies: None as such, but awfully hungry most of the time
Aims: They are hungry, I tell you!
Peculiarities:

• Devolved strain of blind antler men never able to adapt to digestion of earthly materials, developed over time into super-specialized soul-eaters, intellect frittered away with disuse until they became at last semi-immortal, single-minded engines of destruction
• Following consumption of living sentience, psychephage forever able to conjure up personality and project convincing illusion of victim but speech is always a hash of non sequiturs and meaningless soundbites 
• Smells intellect and always stalks/attacks the brainiest people first, if it consumes a brain containing memorized spells, these are instantly and simultaneously cast, targeting any nearby at random
• Projects illusion of surrounding terrain to conceal self from prey until ambush opportunity presents itself
• Sucks out the brains, extracts that certain special something (soul, psyche, whatever), sneezes the remaining tissues out in non-damaging but gratuitous and super-revolting blast
• Do not reproduce, only a handful remain

Treasure: Eschews the material, but perfect copies of 2d12 personalities from across time and space encoded into cellular matrix in abdominal bladder, sorcerers already at work on magical means of information extraction, will pay heavy gp for undamaged specimen

PLAIN STRIDER

Number Appearing: 1-4

Size: Twenty to forty feet tall

Armor: Tough chitinous shell on lower extremities, tentacles and exposed brain soft and squishy, 100% proof against acid, ooze attack

Resilience: Attacks on legs like chopping down good sized tree, brains and soft bits more vulnerable

Intelligence: High but utterly unconcerned with the affairs of lesser beings

Communication: Emits rhythmic ululations, mostly subtle derivations of popular Plain Strider songs 

Disposition: Smug superiority of creature that sits atop the food chain

Violence: Tentacles seize prey, deliver to huge parrot-like beak concealed in lower body cavity, stuns prey with sonic attack (the Song of Hunting), smash or kick with feet

Enemies: None as such, but regards anything human size or smaller as prey

Aims: Hunt and feed, composition/performance of songs

Peculiarities: 

- Apex predator of the Great Lichen Plain, an improbably vast cavern of broken rocky terrain covered with unique variety of growths, teeming with oozes, slimes, puddings and jellies

- Hunts puddings and oozes primarily, but always willing to try something novel

- Communicates via humpback whale-like songs when necessary, mostly sings to express itself as artistic exploration of its nature and place in the cosmos, individuals in constant competition for place in the Plain Strider Top Ten

- Quickly stomp out any non-Striders who attempt one of their songs

Treasure: Beaks sought after by Underworld sentients as raw material for building projects/giant-size armor, sometimes fashioned into the hulls of vessels meant to navigate the Black Ooze River

BLIND ANTLER MEN

Number Appearing: Singly, in small groups, teeming in their thousands
Size: Taller than the average human
Armor: Ornate exoskeletal Underworld survival suits, crafted of manipulated biological tissues
Resilience: As per tough, experienced human warrior plus slow regeneration
Intelligence: Smarter than humans, cosmic awareness
Communication: Unique language characterized by monotone shouting, able to master most spoken languages after extended, highly irritating period of very loud monotone echolalia
Disposition: Aloof, emotionless, eminently logical, frequently distracted by input from numerous unknown senses
Violence: By weapon (enchanted self-heating swords for exterminating trolls, exploding bolas, bio-drones), spells
Enemies: Chaos godlings of the Underworld and their humanoid cultists, untrustworthy interlopers, trolls (an embarrassing degenerate sub-species)
Aims: Accumulation of available knowledge of the cosmos ascertained via array of sensillae (ever-changing rack of "antlers") from comfort of home, hoarding thereof without much in the way of practical application
Peculiarities:
- Slip into inert state of deep observation, sometimes in mid-sentence, when alerted to wide variety of stimulae by sensory array
- Animal/fungus hybrid alien to the Underworld, delivered as hibernating spores on great meteorite that crashed through the surface into their home cavern, now a bewildering metropolis featuring vast group meditation spaces full of motionless antler men standing around perceiving things
- Able to cast limited selection of spells by direct mental manipulation of ambient Chaos in the Underworld with none of the hassle of verbal, gestural, or material components
- Cosmic awareness enhanced by senses known and unknown, consider themselves equal to Chaos godlings in wisdom and stature but require no unseemly worship as do the emotionally starved and stunted godlings
- Bio-technological devices further enhance their capacity to probe the unknown
- Field armies only occasionally but have never lost a battle
- View surface people as menaces due to ability to "taste" greed, hate, irrational fear and other universal human characteristics, all of which make them want to vomit
Treasure: Invaluable Underworld knowledge, fortunes in natural resources, precious metals, gems and crystals (all used for scientific/aesthetic purposes only), weird manufactured goods of dubious use to lesser beings

WIZARD HEADS

Number Appearing: 1-12

Size: Human head plus wee limbs

Armor: None

Resilience: Can withstand physical damage as a human head on wee limbs

Intelligence: Exceptionally brainy

Communication: Speak several languages with high-pitched parody of human speech, mutter to one another in personal language as well as shared telepathic link

Disposition: Mood swings as typical in megalomaniacs

Violence: Dagger, spells, bites like hell

Enemies: Fools who dare interfere with their diabolical schemes

Aims: Identical to immediate ancestor only even crazier/more ambitious

Peculiarities:

- Heinous result of over-indulgence in the black arts, a lifetime of questionable choices/practices, triggered by particularly risky eldritch activity (contacting outer being, casting spells requiring inhuman faculties, etc) whereupon the sorcerer's body suddenly explodes leaving only the head behind which then erupts from within spewing out larval wizard heads, each growing into nearly identical copies (excepting tiny limbs, rows of fangs, and extended jaw) of the original 

- Operate independently but also able to form single super intelligence at need

- Arcane abilities increase in power in direct proportion to the number of heads in proximity (single head equal to fledgling wizard, twelve heads as per arch-mage) 

Treasure: Hoard inherited from original sorcerer

ROBED DEVIL

Number Appearing: 1-6 

Size: Just bigger than human size

Armor: Demi-corporeal form prevents damage from all but enchanted weapons, spells

Resilience: Not so tough if you can hit them

Intelligence: Mentally negligible but believe themselves wise

Communication: Mostly incomprehensible gibbering in vain effort to appear erudite, can indicate assent in all known languages

Disposition: Dutiful, joyless

Violence: Dribbles continuous stream of digestive enzymes, distends hood/mouth to completely engulf human-size targets for agonizing dissolution into entropic sub-particulates, soul-rending claws 

Enemies: As designated by creator

Aims: Singular devotion to duty as assigned by creator

Peculiarities:

- Contrary to popular belief, not actually from Hell 

- Generated via elaborate sorcery using gore-soaked vestments of brutally sacrificed High Priests of Law

- Like to hang around with master, act as enthusiastic sycophants 

- Devoted servants but tragically credulous, can be convinced to betray creator by logical-sounding arguments plus ego-stroking 

Treasure: Frequently assigned to guard treasure troves hoarded by sorcerers of means but otherwise devoid of possessions

TYRANNOCLOPS

Number appearing: One or swarm of larvae
Size: 25' including tail
Armor: Skin like elephant leather, no known vital organ, penetration of eye membranes triggers explosion
Resilience: Tough as a hill giant
Intelligence: Like a steel trap
Communication: Telepathic
Disposition: Inscrutable in general, attacks, seemingly without malice, anything penetrating its personal space
Violence: Lethal red eye-beam, tail lash, curb stomp
Enemies: Feared and avoided by sensible Underworld sentients as an unpredictable menace
Aims: Driven by unfathomable instinct to create new pathways and chambers in the Underworld using eye-beams, guided by inhuman aesthetic sensibility
Peculiarities:
-Eye-beams:
      Red: death energies damaging to all living tissues
      Green: carves tunnels through the underworld like hot knife through butter
      Yellow: probes exposed minds for obscure tidbits of information desirable only to Tyrannoclops
-feeds upon subterranean energies, absorbed through skin
-reproduction ensues upon death, 2d12 larvae rapidly take shape in body cavity, wriggle horribly beneath the skin before erupting forth, weak eye-beams coming on line as they stagger off towards shelter, make war upon one another until only the toughest remains, grows to full size in one week, embarks upon Underworld expansion career
Treasure: keeps no hoard but following a tunneling T-clops may lead to fortunes in gemstones (immune to yellow eye-beams) or reveal previously inaccessible vaults of the Extinct Ones