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A Creature Keeper · Long Island Dungeon Master
It is not hunting the party. It is hunting what the party is carrying, and on a dead world those are the same sentence.
At a glance: CR 1 · levels 1 to 3 · a night-camp predator · the bite deals 1 damage, and that is the whole design.
The sand under the supply pile is dark, and the dark patch is drying at the edges while you watch it. One of the skins has gone soft. There is a single hole in the leather, small enough that you have to find it with a thumb.
A seepworm is a parasite that has never once needed to kill anybody. It smells damp through sixty feet of solid ground, it comes up under whatever is wettest, it takes a mouthful, and it goes back down. Guard the water and it does not leave. It simply moves to the next wettest thing in camp, which is a person, and it moves in.
One worm for a level 1 party. Two for level 3, arriving on separate nights so the party thinks it killed the problem. Three at once is a different encounter and it is a worse one, because the tension here is a slow drip and a swarm empties the whole tension in a round.
Open DM Tools. The seepworm is already sitting in the combat tracker with its AC, hit points and tactics. All three clocks are built: three nights of visits, four skins of water, and the Exhaustion stacking on whoever it moved into. All three tables roll from the table roller, so you never have to find your place on a page at two in the morning.
Senses. tremorsense 60 ft., passive Perception 9
Drawn to. moisture. Open water. Sweat. A wound that has not closed. It does not care which.
Challenge. 1 (200 XP) · a night-camp predator for levels 1 to 3
Moisture Sense. It always knows the direction of the nearest open water or bleeding creature within 60 feet. A sealed skin buys you nothing. A cracked one is a beacon.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 1 piercing damage, and the target makes a DC 13 Constitution saving throw or the seepworm burrows in beneath the skin and the target is Infested.
Infested. The host gains no benefit from drinking: the worm takes it first. At the end of each long rest the host gains 1 level of Exhaustion, and no Exhaustion can be removed while the worm remains.
Cutting it out. An ally with a blade or a hot iron makes a DC 13 Medicine check, dealing 1d6 slashing damage either way. On a success the worm comes out. On a failure it burrows deeper and the next attempt is made with Disadvantage. Left alone it leaves on its own in 1d4 days, engorged.
The Full Skin. A dead seepworm holds every drop it took, roughly a day's water for one person, and it is drinkable. It is also seeded with young. A creature that drinks makes a DC 13 Constitution saving throw or is Infested. It looks and tastes like water, because it is.
Roll it here.
It surfaces under the party's water supply, bites once, and burrows out. It works the skins first, all night, for as long as the skins are the wettest thing in camp. Guard the water or run it dry and the worm takes the next wettest thing, which is a person. The host dehydrates with a full skin on their belt. Kill it and you are holding the second trap: a day's clean-looking water, seeded, and out here nobody pours that into the sand.
Allow me. I have been a chest, a barrel and, on one memorable evening, a soup tureen, so I know a thing or two about being the object nobody looks at twice. This creature is doing my job with none of my charm. It takes a mouthful and it leaves the diner alive, which is either terrible manners or the finest table manners you will ever meet, and I genuinely cannot decide which. Do not let your players kill it in a hurry. Let them go hungry for it first. A course tastes better when the guest has waited.
Roll the first one when you drop the worm into a session. Roll the second once a night, in order or at random, and let the party do the arithmetic themselves. The third is where you put the camp when you want the encounter to land hard.
| d8 | where it found the water |
|---|---|
| 1 | The party's own skins, stacked in the shade of the packs at the middle of camp. |
| 2 | A caravan's water wagon, three days out and already riding lighter than the tally says. |
| 3 | A well that a village has drawn from for four generations and is now drawing from twice. |
| 4 | The wound on the mount the party has been nursing since the last fight. |
| 5 | A cistern under a ruin, sealed for a century, with a crack in it since the spring. |
| 6 | The sweat on a chained work gang, which is why the overseer has stopped counting heads. |
| 7 | A merchant's ice, packed in straw, worth more than the wagon it rides in. |
| 8 | The damp at the bottom of a dry wash, where the party made camp because it was soft. |
| d10 | tonight's tell |
|---|---|
| 1 | A skin is a third lighter than it was, and the sand under it is dark and drying. |
| 2 | One clean puncture in the leather, small enough to miss until it is empty. |
| 3 | The ground under the supply pile is loose, and it was packed hard yesterday. |
| 4 | The mount will not stand where it stood last night and cannot be made to. |
| 5 | Somebody wakes up with a bead of blood on the ankle and no memory of anything. |
| 6 | Whoever took the second watch spent it sitting on the water and does not know why. |
| 7 | A dry stripe of grit across the bedrolls, five feet wide, that nobody walked. |
| 8 | The tally board gets checked twice in one evening, by two different people, an hour apart. |
| 9 | Two skins gone in one night. It has stopped being careful because it is winning. |
| 10 | A skin has been buried in the cool sand under a bedroll, and the sand has been smoothed over it. |
| d6 | the camp |
|---|---|
| 1 | A dry wash with soft footing, which is the best camp for miles and the worst ground. |
| 2 | The lee of a rock shelf, where the party stacked everything on one side out of the wind. |
| 3 | A salt flat, hard as fired clay, where nothing should be able to come up at all. |
| 4 | The edge of a working well, with the whole village asleep on the other side of the wall. |
| 5 | A caravan halt with forty people and one wagon that matters. |
| 6 | Inside a ruin, on the only floor that is not stone, which is why they chose it. |
Every good water encounter needs somebody whose whole job is the water, because a party will argue with a Dungeon Master about hydration and will not argue with a man holding a tally board.
Hadeth, who mends the skins · the caravan's water-carrier: he counts every mouthful out and every mouthful back
Wants. To reach the next well with the tally straight, and to not be the one who explains it
Voice. Quiet, precise, apologetic about numbers. Says the figure twice, in case you missed it
Line. “I am not short. The water is short. There is a difference and it will matter to you soon.”
Seepworms do not travel. They are born where water was and stay where water is, which means one on the road came in with something: a wagon, a herd, a load of quarried stone, a body. Whatever it rode in on is still with the caravan, and it is still damp. Find that, and you have found the nest, and the nest is the actual adventure.
This whole page is a Creature Keeper: one file, offline, no account, yours to keep. Drop it into Gnasher's Grimoire, the free Dungeon Master companion at longislanddungeonmaster.com/grimoire, and the worm, all three tables and the witness land on your shelf beside everything else you run from.
Compatible with fifth edition. Portions derived from the System Reference Document 5.1, © Wizards of the Coast LLC, licensed under Creative Commons Attribution 4.0 International (CC-BY-4.0). The Seepworm is original content © Long Island Dungeon Master, free to use at your table.
Auto-built from every data-dc, data-hp, stat block, preset clock and pre-loaded combatant in this file. Prints on its own sheet.
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