Spawn Of Devastation Drive-In — 'Bug' (1975)

Firebug

No. Enc.:  2d8 (5d10)
Alignment:  Neutral
Movement:  30' (10')
Armor Class:  -2
Hit Dice:  2 hp
Attacks:  1 (Ignition)
Damage:  4d6
Save:  L3
Morale:  12
Hoard Class:  None
XP:  15

The Ancients prided themselves on cataloging every Terran species, from the smallest microbe to the largest cetacean...

...but when The Apocalypse commenced, and fissures rent the earth asunder, prehistoric insects crawled topside...

...AND HASTENED HUMANITY'S DEMISE BY INCINERATING ALL IN THEIR PATHS!!! 

Firebugs are heavy, clawed, 4" long subterranean insects with bizarre physiologies, even for the Mutant Future.  Their carapaces are harder than steel.  Eyeless, they navigate by sound and smell; they also lack conventional digestive systems, rendering them immune to all poisons and diseases.  Firebugs feed exclusively on ash and carbon...

...which they procure by starting raging fires with spark-producing rear antennae.  Combustible materials go up instantly, and denser materials in 1d6 rounds.  And firebugs have no qualms about attacking live prey.  They crawl up their targets and dig in with mighty claws, unleashing ferocious heat that does a sustained 4d6 damage per round.  It takes a successful Breaking Doors roll to remove a smoldering firebug from a victim's flesh, and the extraction causes an additional 1d4 tearing damage.

The creatures require the intense pressures of subterranean environs to survive, and don't live long on the surface, expiring from "the bends" after 3d6 hours topside.  But firebugs spread quickly from region to region  by hitching rides on vehicles, usually by hiding in engine blocks or exhaust systems.

As menacing as firebugs are, they become even more terrible upon encountering ordinary cockroaches...for  they interbreed, creating hideous hybrids with powers far beyond mere fire-starting...!

Mutations:  Echolocation, Energy Blast (Heat) (Modified), Frailty ("Pressure Sensitivity") [D], Natural Armor (Extreme) (x4), Reflective Epidermis (Heat)

Vulcanbug

No. Enc.:  4d6 (6d12)
Alignment:  Chaotic
Movement:  75' (25')
Armor Class:  3
Hit Dice:  2 hp
Attacks:  1 (bite, or ignition)
Damage:  1d4, or 4d6
Save:  L3
Morale:  10
Hoard Class:  None
XP:  9

The 2" long vulcanbugs are the unholy offspring of firebugs and common cockroaches. Burning free from hardened eggcases, they grow to adulthood in a mere 5 hours.

Although retaining the same scorching abilities as firebugs, vulcanbugs are smaller, faster, and unaffected by pressure.  And they eat neither ash nor carbon...for they crave living flesh!  They even prey on their sires, as vulcanbugs cannibalize firebugs on sight.

Vulcanbugs possess something far more terrifying than their appetites:  intelligence.  They learn spoken language through observation, and then apply that knowledge so as to read—and comprehend!—the printed word, going so far as to replicate it with their bodies to communicate.  Some posit that vulcanbugs possess a low-grade telepathy, which explains why a swarm shrieks in unison when one of its fellows is slain.

The insects recognize useful technology...and have no qualms destroying it, if doing so serves their purposes.  They also intuit the "most powerful" member in a group of PCs, "addressing" that individual by name and communicating with them exclusively.  Vulcanbugs may be persuaded to follow orders, through superior force or bribes.

Vulcanbugs are viable hybrids, and reproduce rapidly.  They are highly protective of their eggcases, and shuttle them underground for safekeeping.  But when their offspring hatch, the young metamorphose again, transforming from vulcanbugs...

...into larger, flying, red-hot, glowing vulcanbugs!  These 2nd generation monstrosities have:  1 full Hit Die, AC 1, Fly at a rate of 210' (70'), the same ignition and mental abilities, and XP Values of 25.

Who knows what abominable forms they might take as they breed and evolve...?

Mutations:  Energy Ray (Heat) (Modified), Increased Willpower, Metaconcert, Reflective Epidermis (Heat)