Friday, September 30, 2011

Cave and Tunnel Hazards I (Random Table)

Cave and Tunnel Hazards: Table I (D20)
  1. Mud covers the floor of this tunnel section to a depth of (1d12) feet. It is slippery and nearly impossible to avoid, but could possibly be bridged or climbed around by a sneaky barbarian or thief-type. Base 30% chance that some thing lives within that mud.
  2. Sand covers the sloping floor which tapers to a funnel-like cavity that feeds into a larger chamber below. The loose, sugary sand doesn't really start to slide until someone passes the midle point of the room, at which point it drains out from under trespassers at a very fast rate. Save/Dex Check at -2 penalty or get dragged down into lower chamber (d20x100) feet below. Base 40% chance that the lower chamber is occupied (random encounter).
  3. Poison gas fills the passage for 4d100 feet.
  4. This section of cave/tunnel contains a trapped pocket of flammable gas. Any open flame or firesource will ignite the gas, filling a 4d6 foot area with a burst of pungent green flames that will inflict 2d6 damage to all within range. The sudden burst of light will also disrupt nightvision for 2d10 turns. Roll for Wandering Monster.
  5. The floor suddenly tilts 2d10 degrees in a random direction.
  6. A swarm of tiny translucent-yellow ants that cast a peculiar double shadow in torchlight have riddled the surrounding rock and stonework with a maze of miniscule tunnels to a depth of 1d4 feet in an area roughly 4d10 feet in any given direction, causing the floor, walls and/or celing to all be extremely fragile and prone to collapse if disturbed by loud noise, walking over it, etc. Anyone triggering the collapse will suffer 2d4 damage and be buried under a powdery mass of very splintered and sharp stone while they roll for a Wandering Monster.
  7. A series of sharpened wooden stakes have been set beneath a loose layer of dust, making the floor into a sort of raised spike-trap.
  8. The floor suddenly subsides by 1d10 inches. Make a Dex check or loose balance.
  9. A swarm of up to a thousand little brown bats comes shrieking down the hallway--their usual means of accessing the natural chimney they lair within has been blocked by a small rockslide.
  10. The curious gray mold all over the walls and ceiling of this section give off a noxious poisonous gas if exposed to torchlight, inflicting 1d4 per turn of exposure. Dousing the flames or the lamps/torches will cause the mold to stop exuding toxins.
  11. The floor is damp, but not with water. A dilute form of acid has slowly been accumulating in this area. It is slow acting, but persistent and will slowly dissolve leather footwear, and corrode metals that are dragged along through it. The nuisance acidic residue will persist for 5D10 feet and will wash off easily with water, oil or wine.
  12. Tiny, glistening worms dangle from the ceiling, each one suspended on a wet thread of luminous mucous that is both adhesive and narcotic in composition. Contact with the worm's threads will cause affected surfaces to adhere powerfully to any other surface for 1d4 hours and force a Will Save or suffer hallucinations for the duration. Wine might dissolve the adhesive, but it could possibly make it worse (50% chance of dissolving it or causing double duration).
  13. The floor is covered with a 1d4 inche deep pool of stagnant water that carries a base 40% chance of transmitting some sort of infection or disease. Possibly some form of Dungeon Funk?
  14. One of the walls begins to crumble and collapses into a mound of rock and dirt. Luckily no one was hurt. 30% chance that this uncovers a perviously unknown or unmapped tunnel or passage either above the ceiling or below the floor and leading to some mysterious Sub-Level.
  15. The surfaces of this passage are heavily encrusted with sulfurous compounds, making it look all yellowish and rounded and slightly melted. This location is extremely flammable and will produce terrible, brimstone-like smoke that will suffocate anyone trapped within the passage for more than 4 turns. It is otherwise benign and doesn't even smell very much unless scratched, chipped or ignited by an open flame.
  16. Base 30% chance for every person who passes by this section of wall for it to finally give way and flood the passage with hot, stinking mud for 4d20 feet. It will require 1d4 days for this mud to finally cool down enough to attempt passing through it, but it is sticky and slippery at the same time, making any attempt to traverse it difficult and awkward.
  17. Cracks in the floor are natural vents for a boiling mineral spring below. 40% chance of steam erupting form the cracks when stepped on. There might also be a weak point in the floor that collapses like a pit trap, depositing those caught by it into the mineral springs below.
  18. Ceiling partly collapses for 1d10 feet in a random direction causing 1d4 damage to all caught in the collapse. Some of this debris might need to be shifted or dug out a bit to get past it.
  19. Poison gas fills the passageways in a 4d20 foot radius.
  20. Rickety boards and broken weapon-hafts have been assembled into a make-shift bridge over a sinkhole that extends under each wall and runs to a depth of over 100 feet where it drops into some sort of massive, open space that might or might not have water flowing through it. There is a 10% chance per increment of 100 pounds lugged across the bridge tha tit will finally fail, dumping everything and everyone into the sinkhole to slide down its sides until reaching the yawning gap at the bottom. Perhaps one might make a Dex Check to stop from falling through. but what of everyone else behind them? If the party was smart and had each person go over one at a time, then the sinkhole has a 40% chance to collapse a bit more around the edges, sending anyone within 2d10 feet of the sinkhole tumbling downwards to the gap and what awaits below...hello sub-level!


  1. That's most definitely a NetherWerks table! Acid, hot mud and mucous. There's a very cavey atmosphere too and it's clear you thought deeply about the possibilities.

  2. @Porky: Kinds gross, we know, but it all goes with the environment down there. Caves and tunnels are a lot of fun to use in a game as tehy can get reaqlly confined, then open up into huge pockets or drop down into a subterranean watercourse and so much more. There's a lot more to the average underworld than just corridors and endless series of 10'X10' rooms...


Thanks for your comment. We value your feedback and appreciate your support of our efforts.