Adapting Edward Ludwig’s 1957 atomic-horror classic The Black Scorpion for Barrows & Borderlands means merging 1950s creature-feature panic with a dark, radioactive fantasy frontier.
Rather than treating the monsters as generic giant bugs, we preserve the film’s unique surreal atmosphere—inspired by Willis O'Brien's jerky, nightmare-inducing stop-motion animation—and weave them into the radioactive, black-powder sandbox of the Borderlands.
The Hook: The Volcanic Fracture of San Lorenzo
In the Borderlands, a sudden, violet-tinted volcanic eruption clears away an ancient ridge, exposing a gaping fissure into the deep Underworld.
The Surreal Atmosphere: The ash doesn't just block the sun; it casts an obsidian, dream-like haze over the landscape. Local livestock are found entirely drained of fluids, leaving behind ruined, overturned caravans.
The Rumor: Superstitious border-dwellers whisper that a "Demon Bull" has been unleashed by the volcano.
In reality, it is a brood of prehistoric, irradiated horrors.
Monster Statistics: Grand Black Scorpion
These aren't ordinary arachnids. They are colossal, twitching engines of hunger that move with an uncanny, staggering gait. Their faces are frozen in an eerie, unblinking grimace, and they secrete a highly toxic, glowing obsidian venom.
Hit Dice: $9+3$ (Large)
Armor Class: 3 [16] (Thick, chitinous exoskeleton)
Attacks: 2 Claws ($1\text{d}10$ each), 1 Stinger ($1\text{d}8$ + Lethal Venom)
Move: 120 feet (40 feet)
Special Abilities:
Irradiated Stinger: A target struck by the stinger must make a Save vs. Poison. Failure results in agonizing, immediate death as the blood turns to black sludge. Success still inflicts an additional $2\text{d}6$ radiation damage and triggers a minor mutation roll on the Gamma tables due to the toxic glow.
The Fatal Flaw (The Throat Spot): The creature's heavy plating is nearly impenetrable. However, when it rears up to strike or roar, it exposes a small, pale, milky-white membrane right on its throat.
Attacks targeted specifically at this spot are made at -4 to hit, but a successful strike bypasses all Armor Class (treating it as AC 9 [10]) and deals double damage. Chitinous Shield: Normal black-powder flintlocks and standard cold steel deflect harmlessly off its carapace unless hitting the Fatal Flaw. Only heavy siege weapons, psychics, or high-tier sorcery deal full damage to the main body.
The Obsidian Trench (Dungeon Ecology)
If the party descends into the volcanic rift, they don't find a sterile cave. They enter a vast, echoing subterranean ecosystem cut off from time—a surreal dreamscape of bizarre horrors.
Tactical Encounters & Set Pieces
1. The Lightning Spear Strategy
The local military or tech-scavengers have devised a desperate weapon: a ballista firing a massive iron harpoon trailing a thick copper cable. If the party can anchor the harpoon directly into the vulnerable white throat spot, a Sorcerer or Psychic can channel an elemental lightning spell or kinetic surge directly down the wire, bypassing its hit points entirely to fry it from the inside out.
The Risk: Handling a highly conductive wire while an irradiated titan is thrashing creates a massive hazard. Anyone within 10 feet of the cable when the spell is cast must save or take a portion of the electrical backlash.
2. The Train Ambush
If the scorpions escape the Borderlands and head toward a major settlement, they will target infrastructure. A spectacular encounter involves the characters defending a heavy, black-powder armored locomotive as a pack of scorpions stalks it through a narrow canyon, tearing open the iron roof cars to reach the passengers inside.
Here is a d20 encounter table for the San Lorenzo Volcanic Fissure, blending old-school Barrows & Borderlands danger with the surreal, stop-motion-inspired cosmic horror of 1957 atomic sci-fi.
Encounter Table: The San Lorenzo Fissure (d20)
| d20 | Encounter / Hazard Type | Description & Game Mechanics |
| 1–2 | The Apex Chitin (Encounter) | A lone Grand Black Scorpion stalks the shadows. It hasn't spotted the party yet; it is busy tearing apart and drinking the luminescent fluids of a giant cave worm. If the party remains perfectly still, they might slip by, but metallic noises (like clanking armor) attract it instantly. |
| 3–4 | Brood Swarm (Encounter) | 2d6 Scorpion Hatchlings (each the size of a wolf, 2 HD, 1d6 damage + saving throw vs. poison at +2) burst from a sulfur vent. They are driven by a frantic, twitching hunger and move with uncanny, jagged speed. |
| 5–6 | The Lost Survey Team (Encounter) | The party finds 1d4 crazed, irradiated survivors from a local military or academic expedition. They wear cracked brass hazmat suits, babble about "the clicking in the dark," and are highly paranoid. They might fire their black-powder muskets at shadows—or at the party—out of pure panic. |
| 7–8 | Oily Web Stalker (Encounter) | A Colossal Black Trapdoor Spider (5 HD) leaps from a silk-lined crevice in the basalt wall. Its face is eerily human-like in its stillness. A random character must make a Save vs. Paralysis or be dragged into the dark recess to be slowly digested. |
| 9–10 | The Tremor & The Slime Worm (Hazard) | A sudden volcanic tremor rocks the cavern. Everyone must make a Dexterity check or fall prone. The shaking rouses a Prehistoric Segmented Earthworm (4 HD) from the boiling mud below, which blindly lashes out at anything nearby. |
| 11–12 | Violet Ash Outflow (Hazard) | A geyser of toxic, violet-glowing volcanic ash erupts from a nearby fissure. The air becomes a heavy, dream-like haze. Characters must make a Save vs. Poison or suffer 1d4 Constitution damage from the radioactive soot and experience vivid, terrifying auditory hallucinations of clicking mandibles. |
| 13–14 | The Carnage Site (Discovery) | The wreckage of a stagecoach or military supply wagon dragged down from the surface. A thorough search yields 2d10 gold pieces, a crate of dry black powder (30 shots), and a functional, oversized Pneumatic Harpoon Gun (requires 2 rounds to reload, deals 2d6 piercing damage, treats giant carapaces as AC 5 [14]). |
| 15–16 | Obsidian Resonance (Hazard) | The party enters a cavern lined with jagged, glass-like obsidian spires. The subterranean wind whistling through them creates a bizarre, high-pitched droning frequency. All spellcasting or psychic checks are made at a -2 penalty due to the intense mental interference. |
| 17–18 | Molten Sulphur Mire (Hazard) | The path gives way to a shifting field of boiling, neon-yellow sulfur pools. Navigating the treacherous ledge requires careful movement. Heavy armor increases the risk; any character who slips takes 2d6 fire/acid damage and their armor's effectiveness is permanently reduced by 1 point. |
| 19 | The Giant Crying (Encounter) | The cavern echoes with a bizarre, high-pitched wailing that sounds almost like a human baby, but amplified a hundred times. It is a Giant Tentacled Gastropod (6 HD), a pale, blind mollusk slick with radioactive slime that corrodes metal on contact. |
| 20 | The Mother's Shadow (Encounter) | The temperature suddenly spikes, and the ground rhythmically thumps. The massive, towering silhouette of the Matriarch Black Scorpion passes overhead on a higher rock ledge. She ignores the party unless provoked, but her sheer presence requires a Save vs. Fear to avoid fleeing back up the chasm. |
