We’re Gonna Need a Bigger Boat, and Like Star Trek But Worse…

This begins a new series at Many-Sided Dice about traps and making interesting ones. We’ll dial in on a running format in the coming weeks.


Baldwin carried Kallie over his shoulder, like a sack of barley, pumping his legs and wildly scrabbling to keep his footing and handhold on this and that piece of wall. The creature was mad–really, really mad. It howled and screamed behind them, the whooping noise growing more distinct and close.

Over a low pile of boulders and up the passage he went, banging her shoulder or his knee every dozen feet or so. It was nearly pitch black down here, and he started feeling the weight of earth above and around him closing in—he was lost, or near enough. Shit. And still, the thing was coming on behind them.

A luminescent cavern opened up before him, a stream of some kind half flooding the center. The other side had a number of passages and he felt like he might be able to give the creature the slip. Kallie groaned something, barely rousing to a self of awareness while he carried her. As he splashed his way across the shallow stream, he felt his legs go cold.

History: Hamish Brut, a traveling scholar and naturalist of the College of Lore back in the days of the Third Empire—when the demihumans and truly inhuman civilizations were purged and flung far into the remote corners of the world—was a collector of stories and culture. His most famous works included a six volume treatise on the religions of the “natives of the sea”. It included detailed anthologies of Merpeople history, the lairs of feared monsters of the deep, and Sahuagin temples architecture.

Upon his return, many bards took to his writings and in the next few dozen years, after the death of the Empire, it became in vogue for highborn to dip into his detailed writings and appropriate some of its secrets for their own estates and manses. Badwater (or sug’alai’nss, in Aquatic) was a fashionable way of protecting one property. Originally used, according to Brut’s study, in Sahuagin rituals to restrain those to be sacrificed to the Rokean, it served just as well a purpose to drown and bury the unwary burglars of the civilized world.

System: Like all Sahuagin traps, detection is extremely difficult from outside the water. Badwater is slightly heavier than water, sinking below normal water when created or poured into it. Normally, there is at least 3 ft of normal water above the 5ft of Badwater. Noticing the difference in viscosity and clarity below a layer of normal water requires a Passive Perception of 19, noticing it while looking from below the surface (by being submerged) is made with advantage (+5 to Passive Perception).

Most often, this arrangement of water is created as a deep pool or pond in a large chamber with at least 30ft. of swimming across. In the years when the trap was popular, it was not uncommon to have entire underground pools with valuables delicately contained at the bottom or in the middle to lure the unwary.

Upon noticing the underlying Badwater, one may make a Nature Check DC 14 to determine the racial influence of the submerged Badwater, that it resembles a substance as outlined in the “History” section of the trap. Beating the check by 5 (19 or higher total) one also understands the mechanics below on top of that.

If lightly disturbed, by a foot or a stick, Badwater doesn’t react at all. Its properties remain dormant. But, with great agitation—a whole body thrashing in it, multiple people kicking up water moving around it, etc.—the Badwater begins to rapidly expand, crystalize, and begin a chain-reaction with the normal water resting on it.

Swimming across (and above) the Badwater for one individual creates no problem unless they fail their Athletics check (to swim) and sink down a few feet (seemingly harmlessly) into the pool and disturb it. Multiple individuals swimming across (2) will disturb it. When people are deciding to cross the water, wait until everyone has freely determined whether they’re swimming or staying to maximize the number committing before going into the trap. If in combat, the Badwater goes off at Initiative 10 on the turn following the disturbances that trigger it.

Once the Badwater is disturbed, roll 1d20 for every individual disturbing it and select the highest. That sets the DC for the necessary STR check they must make at the start of their turn in order to continue swimming or retreating. The more individuals kicking up water, the more fiercly it reacts. On a successful Save, the individual may spend half their movement to break free from the rapidly hardening and encompassing mass of icy crystal and continue their turn. On a failure, they are considered Grappled. They may attempt to break the grapple as normal against the same DC as the original STR save minus 2 for every individual no longer in the water (so, if three people were in the water when it triggered, and one managed to get out before the third person’s turn, their grapple DC would be 2 less than the original Save; if two got out, it would be 4 less).

On the next round, anyone in the water when the Badwater goes (initiative 10) is Restrained and Grappled, the DM should roll 1d4 for everyone in the water and add that to the last DC for the trap to set the Break DC to anyone attempting to use tools to chip and shatter away at the icy glass and free them. Anyone trapped in the water/ice is subject to the Suffocation rules and takes 1d8 times the number of people in the water in Cold damage at the end of the Badwater’s turn this and each subsequent round. After this round, however, all who were in the water are trapped and encased, and the water has expanded and hardened around them. Others stepping onto the icy substance don’t sink in and are not subject to the trap otherwise.

Breaking people out of the crystalline ice substance requires the appropriate tools (picks, Mason’s tools) or the attempt to break through is disadvantaged (and resistant to most forms of damage). As the substance is not exactly ice, it does not react to fire as though it were. Doing raw damage to the ice is slower, but should one do twice the Break DC in damage all at once (after resistance), the icy-glass shatters and frees the individual. A mixture of whale marrow and Diller’s oil (Herbalism Kit, DC 19 to make in 1d4 rounds; advantaged if one recognizes the trap as being Sahuagin in origin) will effortlessly dissolve the crystalline structure in an exothermic reaction that will restore half the Cold damage taken by the victim to their hp.

Making the Trap Easier/Harder:

  • Placement – Whether this trap registers for your players as one will depend on how it is placed. If there are many pools or streams and none of them ever have dangers, then this one will come as a huge surprise. On the otherhand, placing a treasure chest beneath the water may entice some players but alert others to how strange that must be and give them reason for caution.
  • Trigger – No doubt, the depth of the Badwater underneath the normal water is the driving factor. If there’s 10ft of normal water on top, then it is only likely to catch the very bad swimmer and its more likely that people pass over it without a problem. The deeper the water, the more likely people look to floating across the surface instead of swimming. All easier. On the otherhand, making it a thinner channel of water on top or a seemingly shallower stream will encourage more people to cross together, increasing the lethality of the trap’s mechanics.
  • Combat – Given that this trap thrives as a stream or creek, a combat encounter that draws players over the stream and in two’s or three’s is very dangerous. Maybe a monster or a bandit they’re hunting for that they see and chase after. On the otherhand, them running into a large encounter that forces them to retreat or flee, and coming across a stream, that will make things very lethal. Combat with this trap is risky, but can be worth it.


For the fourth time—at least he thought it was the fourth time—since he’d found himself stuck here, Kurt tried to kill himself. He ran headlong at the wall, over and over, until he couldn’t see and couldn’t stand and then he beat his head against the floor—bloody and darkly. He lost consciousness several times. He lost his sense of time and self.

By the time he’d healed the breaks and bruises, weeks he imagined, he started sobbing again. This time, it went for what he imagined to be several days. Less time than last time, he guessed. He begged again. And he prayed again.

And he cursed himself and everything, yet again. Had it been more weeks? A month? Two?

And then, finding his way to his feet and pacing his cell—he decided to kill himself.

History: Very few know about the Oerthi, the alien race of Machiavellian conquerors that hide in the farthest and darkest corners of the world. They came to this plane in search of manifest destiny, seeking to turn it into a new wasteland of power and subjugation. But, they were fought back, the doors closed behind them when they were cast back out into their dimension. Now the few that remained seek to open the way again and in the heart of the Mournlands, in the glory of the Chasm, the mind-flayers plot and tinker with the wall between realities.

The Thedlock was created on this world, and the agents of the Illlithids have spread them to careful and secret places in the last dozen years. Their agents have raided many deep and rich haunts of power, the Thedlock softens the mind of lesser creatures, making them more vulnerable to psionic powers. One finds them in places either recently scouted by Illithids or left in place to guard them while they raid some ancient artifact of power.

System: At a glance, a Thedlock looks like something desireable. It attunes to the closest non-psionic mind and appears to be something valuable but expectable. For the dwarvish fighter coming on an ancient jungle temple of the elves, he might see the Thedlock as the long desiccated skeleton of a dwarf collapsed on top of an equally ancient elvish corpse plunging an axe into its chest. For the human abjurer, it may look exactly like a wavering arcane ward exactly like their own surrounding the door–firm, but familiar. For the halfling ranger, it will look like a snarling, wild-eyed dying wolf with a broken leg that appears to be simply fever mad and trying to drag itself away. It appears for all intelligent creatures as it appears to that first closest mind.

Passive Perception DC 16 to notice the light humming sound in the back of one’s mind being near the Thedlock’s image. An Arcane check DC 18 should be offered to any sensitive enough to notice the hum. On a success, they recognize it as the buzz of mind-influencing power; beating the check by 5 reveals that it is the same signature as direct Psionic manipulation of the brain by Illithid sources. Anyone recognizing the signature (having made the Arcane check with a 23 or higher) are unaffected by the Thedlock. Anyone having only basically succeeded at the Arcane check may make an Int Save (DC 18 if they were the first closest mind that influenced the look of the Thedlock, advantaged if they were not and the Thelock is basing itself off of someone else’s mind). On a success and for those unaffected, the Thedlock appears as a smooth white metal ball about the size of a baby’s head. It is flawlessly machines with barely discernible grooves and an inert feel to it.

Given its recent invention, there is no Arcane or knowledge-based check possible for determining exactly what it does or how it works. Only the previous checks’ hints at its origins.

It is never, ever necessary to touch the Thedlock. In fact, the whole point of the trap is to cover the tracks of and drive to madness the foolish and curious. The cautious have little to fear from it. Whether revealed to be a white ball or still looking like the desirable thing, should anyone come within 1ft of the Thedlock, it triggers.

Carefully describe what happens openly with the players.

The closest person (and if there is a seeming tie, the one with the lowest Intelligence) is transported wholly into an alien plane, they see brief flashes of light and horrorful landscapes of desolate plains and tundra covered by a black and purple sky and littered with ugly cities in crude and off-putting geometric arrangements. They feel as though their flying and they find themselves being plunged into a cell in one of the buildings of one of these cities. A seamless box, 10ft. by 10ft. by 10ft. No windows. No food. Just darkness and the light hum of something that makes them nauseated and yet satiated at the same time.

Their possessions are all left behind. Inform the remaining players that the stuff is lying there and the ball is gone. Weapons, armor, money, everything. Let them talk for a moment about what they want to do. Keep track of the things they use (spell slots, consumable items, etc.).

The person trapped in the other dimension should be allowed to try and get out. The walls, however, are nearly indestructible—but let them try openly without comment and record the damage they try and do while describing that it seems to have little or minimal effect. If they stop to do any kind of investigation, they’ll find that the walls are adamantine and seamless. While in the box, they’re cut off from their God, Patron, and the terrestrial powers they once had. That part of their world is silent now.

Give them a moment or two to try things to break out. Then hit them with 10d6 Psychic damage for the attempt, give them an Intelligence Save of 12 to take half damage. It just informs them they can’t be so reckless.

Back to the party, as they try to do things. Take up stuff, attempt to divine or summon or locate… failures. But make the failures plausible.

Back to the person. Describe that days go by. Weeks. If they attempt to do anything to escape they are shocked again. They get no long rest or short rest from being here. If they fall unconscious or die, they are revived by tall, gaunt and pale figures with tentacles that appear blurry in the dark. If they try and attack them, more shocking and Mind Blasts and pain. Unconsciousness.

Describe the experience as months of torture and hunger and dying and resurrection and alien things. Over and over. Keep hinting at an obvious way to get out that they overlooked. Be devious about this. From the get to, give the impression there is a way to break out or a high enough Investigation to find something. Give them hope.

Every time they “die” in an attempt to do something, the DM may change one their Backgrounds (Ideals, Personality, Bond, Flaw). After all four have been replaced, the trap’s effects end. If the player completely stops taking the bait to try and break out or try and fight the creatures (let him really hurt and damage them when he sees them, to encourage more fighting and hope for killing them off), the trap ends.

When the trap ends, the victim is standing exactly where he had been, holding the ball, fully clothed and geared up, exactly as they were. The prison was in his mind. He spent years away in a hell that wasn’t real. Tell the other players that their actions were part of the victim’s fevered dreams of what they would do–return them what they spent or used to break him out or find him. It never happened.

The cost was some of his sanity in the dark. His backgrounds changed. This will create a new RP problem for the character who may be just as he was, but will only get Inspiration back by giving into and playing out the horrific effects through the new backgrounds. The DM is encouraged to change ideals and personalities to be more hopeless or angry, change bonds to maybe whatever or wherever the character ever felt safest, change flaws to claustrophobia or overabundant caution. One may, through downtime, work through one’s issues and change one’s Backgrounds to something more accommodating.

Making the Trap Easier/Harder:

  • Placement – Making the trap more likely to trigger only takes placing the Thedlock amidst other objects and materials. Placing it nakedly in an open hallway is suspicious and people will investigate and avoid it, but placing it in the middle of a body-strewn battlefield or a pile of treasure in a hidden cache is less suspicious.
  • Trigger – If one wants to make the trap less likely to “go off”, make the radius of triggering smaller–even limiting it to touch. To make it more likely to go off, increase that radius to 5ft or more. Also, consider how you describe the “mirage” and what tells you give. It wants to turn into something that validates the role the character believes they have.
  • Combat – This is a very non-combat trap. It happens instantly. It lasts for a fraction of a second. The lingering effects don’t impact anything in the short-term. Putting this in combat will just confuse the combat, avoid it if possible.

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