Swamp Encounters
Choose one of these 21 swamp encounters, read its opening aloud, and start playing. Each gives a concrete setup, a trigger, actions, consequences, and ways to finish or withdraw.
Each Setup includes an expandable DM hex map with a numbered key and a printable SVG download. Adjacent hex centers are 5 feet apart, with north up. Maps include DM information. Unstated dimensions and placements are illustrative; stated distances and encounter text take precedence. On outdoor maps, the dashed outer edge marks the illustrated area, not a wall. Heights and depths appear in the key.
Choose an Encounter
Suggested levels assume four adventurers with some resources remaining; they are starting points, not guaranteed difficulty ratings. Times estimate minutes of table play. Peaceful scenes can fit other levels; check the listed creature if a fight starts.
| Encounter | Levels | Type | Time | Immediate problem |
|---|---|---|---|---|
| 1. Will-o’-Wisp’s Temptation | 3–5 | Exploration / combat | 15–25 | A moving light leads toward a visibly unsafe bog. |
| 2. Bog Wraith’s Ambush | 6–9 | Dangerous combat / remembrance | 20–30 | A dead keeper blocks a causeway until a stolen marker is restored. |
| 3. Swamp Hag’s Bargain | 4–6 | Social / investigation | 20–30 | A hag offers a route in exchange for a disputed keepsake. |
| 4. Quicksand Peril | 2–5 | Original rescue hazard | 15–20 | Fresh pole marks reveal a dangerous mud patch. |
| 5. Crocodile Ambush | 3–5 | Combat / bypass | 15–25 | Two predators guard a broken fish trap beside the ford. |
| 6. Marsh Gas Ignition | 3–6 | Original hazard | 10–20 | Visible bubbling and dead reeds warn against open flame. |
| 7. Lizardfolk Border Ambush | 3–5 | Social / combat | 20–25 | A patrol wants proof the party did not empty its traps. |
| 8. Swampy Fog Ambush | 2–4 | Navigation / combat | 15–25 | A false guide tries to separate travelers in a fog bank. |
| 9. Mosquito Swarm | 2–4 | Combat / containment | 10–20 | A buzzing cloud gathers around an exposed food basket. |
| 10. Quagmire Beast | 5–8 | Combat / rescue | 20–30 | A plant mass clutches a drifting supply raft. |
| 11. Swamp Witch’s Choice | Any | Social / investigation | 20–25 | A herbalist wants a disputed charm returned to its owner. |
| 12. Poisonous Thicket | 2–5 | Original hazard / exploration | 15–20 | A visible irritant hedge blocks an old trail. |
| 13. Swamp Elemental Convergence | 5–8 | Repair / combat | 20–30 | A living eddy circles a jammed drainage wheel. |
| 14. Fungal Infestation | 2–4 | Combat / containment | 15–25 | Slow fungi threaten a village’s raised food store. |
| 15. Marsh Sprite Lanterns | 1–4 | Social / navigation | 10–20 | Tiny guides moved the public lanterns into a playful pattern. |
| 16. Murmuring Marsh Spirits | Any | Social / remembrance | 15–20 | A harmless vision asks visitors to replace a memorial bell. |
| 17. Sinkhole Ambush | 3–5 | Original hazard / combat | 15–25 | A sagging boardwalk reveals both a safe bank and scavengers below. |
| 18. Swamp Druid’s Challenge | 2–5 | Social / restoration | 15–25 | A keeper asks travelers to restore a fish passage. |
| 19. Abandoned Swamp Village | 3–5 | Combat / investigation | 20–30 | Three undead watch a public ledger in a flooded square. |
| 20. Marsh Marauders | 3–5 | Social / combat | 20–25 | Boat raiders demand payment for a public landing. |
| 21. Swamp Fever Outbreak | Any | Investigation / aid | 20–30 | A camp needs its contaminated water supply replaced. |
Running This Collection
Use SRD 5.1 creature statistics; expand a reference inside each scene for the actual attacks, defenses, senses, and actions. HP is per creature. A damage entry such as 4 (1d4 + 2) means use the average or roll, not both. A weapon range of 30/120 means normal/long range; attacks beyond normal range have disadvantage. Use listed ability modifiers for unlisted checks or saves. All references are freely available under CC BY 4.0.
Original procedures: scene-specific checks, timers, magical scenery, bargains, and hazard damage below are original design, not universal official rules or extra creature abilities. Use a stated check only when its approach is uncertain; a sound plan that removes the danger can succeed without rolling. Roll initiative before hostile actions, apply hiding and surprise normally, and do not treat dim light as physical cover. Melee reach and multiattack limits are in the references. Unless specified, scenes occur by daylight outdoors; dark interiors need a light source.
1. Will-o’-Wisp’s Temptation
At a glance: levels 3–5 | Exploration / combat | 15–25 minutes | Creatures: 1 × Will-o-Wisp.
A pale light pauses beyond the reeds. At your feet, a half-sunken trail marker points in the other direction.
Setup. A 70-foot marsh clearing has a firm south bank and east boardwalk. One will-o’-wisp hovers 30 feet north over dark mud. The original bog hazard occupies a visible 20-foot patch; it is not a new wisp power.
DM hex map: Will-o'-Wisp's Temptation
Trigger. Following the light into the patch starts initiative; the wisp does not automatically charm travelers.
Run it. A DC 12 Athletics action lets a creature pull free of the mud, which otherwise counts as difficult terrain and reduces its speed to 0 while caught. An adjacent helper with rope frees it using an action without a roll. The wisp attacks only isolated creatures in the patch, using actual Shock and Consume Life limits. The east boardwalk bypasses it.
Resolution and reward. The marker leads to a 15 gp survey tin and a safe camp. Refusing the lure solves the navigation problem without combat.
Adjust. Easier: a rescue rope already spans the patch. Harder: move a loose plank to open the boardwalk.
SRD reference: Will-o-Wisp
Tiny undead, chaotic evil
AC 19 | HP 22 (9d4) | Speed 0 ft., fly 50 ft. (hover) | CR 2 (450 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 1 (−5) | 28 (+9) | 10 (+0) | 13 (+1) | 14 (+2) | 11 (+0) |
- Damage Resistances: acid, cold, fire, necrotic, thunder; bludgeoning, piercing, and slashing from nonmagical attacks
- Damage Immunities: lightning, poison
- Condition Immunities: exhaustion, grappled, paralyzed, poisoned, prone, restrained, unconscious
- Senses: darkvision 120 ft., passive Perception 12
- Languages: the languages it knew in life
Consume Life. As a bonus action, the will–o’–wisp can target one creature it can see within 5 feet of it that has 0 hit points and is still alive. The target must succeed on a DC 10 Constitution saving throw against this magic or die. If the target dies, the will–o’–wisp regains 10 (3d6) hit points.
Ephemeral. The will–o’–wisp can’t wear or carry anything.
Incorporeal Movement. The will–o’–wisp can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.
Variable Illumination. The will–o’–wisp sheds bright light in a 5–to 20–foot radius and dim light for an additional number of feet equal to the chosen radius. The will–o’–wisp can alter the radius as a bonus action.
Actions
Shock. Melee Spell Attack: +4 to hit, reach 5 ft., one creature. Hit: 9 (2d8) lightning damage.
Invisibility. The will–o’–wisp and its light magically become invisible until it attacks or uses its Consume Life, or until its concentration ends (as if concentrating on a spell).
2. Bog Wraith’s Ambush
At a glance: levels 6–9 | Dangerous combat / remembrance | 20–30 minutes | Creatures: 1 × Wraith.
A dark figure rises beside the causeway. Its hand points toward an empty name-stone socket.
Setup. A 60-foot stone causeway runs south to north across shallow marsh. One wraith hovers 30 feet north. The missing stone lies visibly on the safe west verge 10 feet from the entrance; no invented cold attack is added.
DM hex map: Bog Wraith's Ambush
Trigger. Crossing the socket’s line without restoring the stone triggers hostility.
Run it. An adjacent action seats the stone and releases the original haunting, even after combat begins. Otherwise use actual Life Drain, maximum-HP reduction, and printed resistances; do not replace those with ordinary weapon damage. The wraith remains within the causeway in this scene, allowing southern retreat. It does not automatically create more undead without meeting its printed conditions.
Resolution and reward. Restoration exposes a 60 gp donation purse and a map of the northern levees. Passing east takes a 1-hour detour.
Adjust. Easier: stone is beside its slot. Longer: confirm the keeper’s name from a visible inscription before seating it.
SRD reference: Wraith
Medium undead, neutral evil
AC 13 | HP 67 (9d8 + 27) | Speed 0 ft., fly 60 ft. (hover) | CR 5 (1,800 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 6 (−2) | 16 (+3) | 16 (+3) | 12 (+1) | 14 (+2) | 15 (+2) |
- Damage Resistances: acid, cold, fire, lightning, thunder; bludgeoning, piercing, and slashing from nonmagical attacks that aren’t silvered
- Damage Immunities: necrotic, poison
- Condition Immunities: charmed, exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained
- Senses: darkvision 60 ft., passive Perception 12
- Languages: the languages it knew in life
Incorporeal Movement. The wraith can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.
Sunlight Sensitivity. While in sunlight, the wraith has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Actions
Life Drain. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 21 (4d8 + 3) necrotic damage. The target must succeed on a DC 14 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.
Create Specter. The wraith targets a humanoid within 10 feet of it that has been dead for no longer than 1 minute and died violently. The target’s spirit rises as a specter in the space of its corpse or in the nearest unoccupied space. The specter is under the wraith’s control. The wraith can have no more than seven specters under its control at one time.
3. Swamp Hag’s Bargain
At a glance: levels 4–6 | Social / investigation | 20–30 minutes | Creatures: 1 × Green Hag.
A crooked figure waits behind a reed screen. “Your road for my necklace. It is under that stump, where thieves left it.”
Setup. A 60-foot firm island has south landing and east causeway. One green hag waits 30 feet north; a necklace lies openly beneath a west stump. The party has no automatic curse merely for arriving.
DM hex map: Swamp Hag's Bargain
Trigger. She offers a safe route map if the necklace is returned.
Run it. The necklace’s inscription identifies a living local owner. Returning it to the hag earns the promised map; returning it to that owner later earns 30 gp instead. She accepts a truthful explanation and 10 gp compensation with DC 13 Persuasion. Failure leaves refusal and retreat open. She does not cast remove curse or bind unspoken terms through invented powers.
Resolution and reward. The map identifies three actual causeway markers. A scratched duplicate of those markers can be copied from the stump with a 10-minute search.
Adjust. Easier: she accepts the explanation automatically. Longer: meet the necklace’s owner at the island landing.
SRD reference: Green Hag
Medium fey, neutral evil
AC 17 (natural armor) | HP 82 (11d8 + 33) | Speed 30 ft. | CR 3 (700 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 12 (+1) | 16 (+3) | 13 (+1) | 14 (+2) | 14 (+2) |
- Skills: Arcana +3, Deception +4, Perception +4, Stealth +3
- Senses: darkvision 60 ft., passive Perception 14
- Languages: Common, Draconic, Sylvan
Amphibious. The hag can breathe air and water.
Innate Spellcasting. The hag’s innate spellcasting ability is Charisma (spell save DC 12). She can innately cast the following spells, requiring no material components: At will: dancing lights, minor illusion, vicious mockery
Mimicry. The hag can mimic animal sounds and humanoid voices. A creature that hears the sounds can tell they are imitations with a successful DC 14 Wisdom (Insight) check.
Actions
Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage.
Illusory Appearance. The hag covers herself and anything she is wearing or carrying with a magical illusion that makes her look like another creature of her general size and humanoid shape. The illusion ends if the hag takes a bonus action to end it or if she dies. The changes wrought by this effect fail to hold up to physical inspection. For example, the hag could appear to have smooth skin, but someone touching her would feel her rough flesh. Otherwise, a creature must take an action to visually inspect the illusion and succeed on a DC 20 Intelligence (Investigation) check to discern that the hag is disguised.
Invisible Passage. The hag magically turns invisible until she attacks or casts a spell, or until her concentration ends (as if concentrating on a spell). While invisible, she leaves no physical evidence of her passage, so she can be tracked only by magic. Any equipment she wears or carries is invisible with her.
4. Quicksand Peril
At a glance: levels 2–5 | Original rescue hazard | 15–20 minutes | Creatures: No combat creatures.
A broken walking pole stands upright in smooth mud. Fresh footprints stop at its edge.
Setup. A 50-foot marsh path has firm south and east banks. A visibly distinct 10-foot mud patch blocks the direct northern route; a 20-minute east detour stays dry. This scene uses original simplified bog rules, not a claim about official quicksand mechanics.
DM hex map: Quicksand Peril
Trigger. A creature stepping into the patch is caught and has speed 0 until freed.
Run it. An action and DC 12 Athletics frees the creature onto an adjacent firm square. A helper on firm ground can instead use an action with a secured rope to pull it out automatically. Failure loses only the action; no automatic sinking countdown or suffocation is added. Testing with a pole identifies firm edges without a check.
Resolution and reward. A safely reached pack on the far bank holds 12 gp and a map of the next causeway. Taking the detour reaches the same bank.
Adjust. Easier: rope already crosses the patch. Harder: the safe detour takes 1 hour.
5. Crocodile Ambush
At a glance: levels 3–5 | Combat / bypass | 15–25 minutes | Creatures: 2 × Crocodile.
Two ridged backs remain just above the water. Torn fish baskets rock against the stepping stones.
Setup. A 30-foot-wide, 3-foot-deep ford connects south and north banks. Two crocodiles wait 20 feet ahead near the fish; a firm east detour takes 15 minutes. Reveal their backs before attacks rather than granting automatic surprise.
DM hex map: Crocodile Ambush
Trigger. Entering within 5 feet of the baskets draws a warning lunge, then initiative.
Run it. Throwing a fish basket downstream distracts both for 1 minute and clears the ford. If fighting, use actual Bite grapple and escape DC, plus normal underwater combat restrictions. They retreat into water after one dies. Neither gains a death roll or extra drag attack; moving a grappled victim uses the usual movement rules.
Resolution and reward. The trap’s owner pays 15 gp for returning its marked tag and clearing the ford. Recoverable coins total 8 gp in a lost pouch.
Adjust. Easier: 1 crocodile. Harder: moving the basket first requires a 10-foot pole.
SRD reference: Crocodile
Large beast, unaligned
AC 12 (natural armor) | HP 19 (3d10 + 3) | Speed 20 ft., swim 30 ft. | CR 1/2 (100 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 15 (+2) | 10 (+0) | 13 (+1) | 2 (−4) | 10 (+0) | 5 (−3) |
- Skills: Stealth +2
- Senses: passive Perception 10
- Languages: —
Hold Breath. The crocodile can hold its breath for 15 minutes.
Actions
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 7 (1d10 + 2) piercing damage, and the target is grappled (escape DC 12). Until this grapple ends, the target is restrained, and the crocodile can’t bite another target.
6. Marsh Gas Ignition
At a glance: levels 3–6 | Original hazard | 10–20 minutes | Creatures: No combat creatures.
Bubbles break through a green film. A blackened torch lies beside a sign warning travelers to hood their lamps.
Setup. A 40-foot boardwalk crosses a 20-foot visibly marked gas pocket. Firm banks and an eastern 20-minute bypass remain available. The gas procedure is original; it does not make every swamp explode.
DM hex map: Marsh Gas Ignition
Trigger. An open flame entering the pocket triggers one ignition, after initiative if characters are already acting under pressure.
Run it. Creatures in the pocket make DC 13 Dexterity saves: 2d6 fire on failure, half on success. It burns out immediately and cannot reignite for 1 hour. Hooding or extinguishing flames before crossing avoids the trigger without a check; cold light also works. No hidden source ignites it after a successful precaution.
Resolution and reward. The far bank holds a 15 gp oilskin map case marking other gas pockets. Failure leaves the boardwalk standing and retreat possible.
Adjust. Easier: the warning includes a clear drawing. Harder: help another traveler shield their visible torch before crossing.
7. Lizardfolk Border Ambush
At a glance: levels 3–5 | Social / combat | 20–25 minutes | Creatures: 2 × Lizardfolk.
Two scaled hunters rise beside a canoe. One holds an empty trap and points to your packs.
Setup. A 60-foot firm bank has south trail and east landing. Two lizardfolk stand 25 feet ahead by a shallow channel; reeds give visual concealment only where they block sight. They speak Draconic and can use gestures for the trap dispute.
DM hex map: Lizardfolk Border Ambush
Trigger. They demand to inspect fish or trap tags before letting the party use their canoe landing.
Run it. Showing different supplies resolves it without a check. Offering a day’s food or DC 12 Persuasion with a concrete explanation earns a truce. Refusal permits a 30-minute east detour. In combat use actual Multiattack and printed weapons; patrol members retreat when one falls, taking their own canoe rather than automatically sinking the party’s gear.
Resolution and reward. Cooperation earns a marked safe landing and information about a recent poacher’s red boat. Their purse contains 15 gp if recovered.
Adjust. Easier: one hunter already suspects the red boat. Harder: 3 visible lizardfolk.
SRD reference: Lizardfolk
Medium humanoid (lizardfolk), neutral
AC 15 (natural armor, shield) | HP 22 (4d8 + 4) | Speed 30 ft., swim 30 ft. | CR 1/2 (100 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 15 (+2) | 10 (+0) | 13 (+1) | 7 (−2) | 12 (+1) | 7 (−2) |
- Skills: Perception +3, Stealth +4, Survival +5
- Senses: passive Perception 13
- Languages: Draconic
Hold Breath. The lizardfolk can hold its breath for 15 minutes.
Actions
Multiattack. The lizardfolk makes two melee attacks, each one with a different weapon.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Heavy Club. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage.
Javelin. Melee or Ranged Weapon Attack: +4 to hit, reach 5 ft. or range 30/120 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Spiked Shield. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
8. Swampy Fog Ambush
At a glance: levels 2–4 | Navigation / combat | 15–25 minutes | Creatures: 2 × Bandit.
A voice offers a shortcut from the reeds. Through the fog, a real boardwalk rail remains visible to your right.
Setup. A 60-foot boardwalk has south retreat and north continuation. Original fog heavily obscures beyond 10 feet. Two bandits stand openly at the first north post 20 feet ahead, one posing as a guide; their route leads to a firm side island, not a concealed drowning pit.
DM hex map: Swampy Fog Ambush
Trigger. They request 3 gp for the supposed shortcut.
Run it. Following the continuous rail reaches the north end without a check and bypasses the offer. Questioning their map reveals it repeats the boardwalk’s route; no roll is needed when compared with the posted sign. If attacked they use actual weapons and flee after one falls. Fog affects their sight too and grants no automatic accurate shooting.
Resolution and reward. The north sign identifies a safe public camp. Their recovered purse holds 10 gp and the original stolen guide’s badge.
Adjust. Easier: the badge is visibly mismatched. Longer: locate the actual guide at the public camp.
SRD reference: Bandit
Medium humanoid (any race), any non–lawful alignment
AC 12 (leather armor) | HP 11 (2d8 + 2) | Speed 30 ft. | CR 1/8 (25 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 11 (+0) | 12 (+1) | 12 (+1) | 10 (+0) | 10 (+0) | 10 (+0) |
- Senses: passive Perception 10
- Languages: any one language (usually Common)
Actions
Scimitar. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) slashing damage.
Light Crossbow. Ranged Weapon Attack: +3 to hit, range 80 ft./320 ft., one target. Hit: 5 (1d8 + 1) piercing damage. Bandits rove in gangs and are sometimes led by thugs, veterans, or spellcasters. Not all bandits are evil. Oppression, drought, disease, or famine can often drive otherwise honest folk to a life of banditry.
Pirates are bandits of the high seas. They might be freebooters interested only in treasure and murder, or they might be privateers sanctioned by the crown to attack and plunder an enemy nation’s vessels.
9. Mosquito Swarm
At a glance: levels 2–4 | Combat / containment | 10–20 minutes | Creatures: 1 × Swarm of Insects.
A dark cloud rises from a basket at the landing. A shuttered storage hut stands just beyond it.
Setup. A 40-foot dry island has south landing and east boardwalk. One swarm of insects occupies the central basket 20 feet ahead, replacing invented giant mosquitoes. Use the listed swarm unchanged, without adding flight or blood drain.
DM hex map: Mosquito Swarm
Trigger. Touching the basket disturbs the swarm, which moves normally at its printed speed.
Run it. Closing the basket’s loose lid with a 10-foot pole takes an action and contains the swarm in this original scene. Walking around the west edge stays beyond its space and needs no check. If fighting, use actual Bites, swarm resistances, and damage change at half HP. No automatic disease applies.
Resolution and reward. The basket’s owner’s purse holds 12 gp, offered for saving the food. The hut provides a dry rest spot once its ordinary door is opened.
Adjust. Easier: lid is already partly shut. Harder: move a crate to reach the pole safely.
SRD reference: Swarm of Insects
Medium swarm of Tiny beasts, unaligned
AC 12 (natural armor) | HP 22 (5d8) | Speed 20 ft., climb 20 ft. | CR 1/2 (100 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 3 (−4) | 13 (+1) | 10 (+0) | 1 (−5) | 7 (−2) | 1 (−5) |
- Damage Resistances: bludgeoning, piercing, slashing
- Condition Immunities: charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
- Senses: blindsight 10 ft., passive Perception 8
- Languages: —
Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny insect. The swarm can’t regain hit points or gain temporary hit points.
Actions
Bites. Melee Weapon Attack: +3 to hit, reach 0 ft., one target in the swarm’s space. Hit: 10 (4d4) piercing damage, or 5 (2d4) piercing damage if the swarm has half of its hit points or fewer.
10. Quagmire Beast
At a glance: levels 5–8 | Combat / rescue | 20–30 minutes | Creatures: 1 × Shambling Mound.
A mound of wet vines shifts against the current. A rope from its tangle still leads to a stranded raft.
Setup. A 60-foot marsh inlet has firm south bank and east causeway. One shambling mound stands 30 feet north in shallow water; an unoccupied supply raft is tangled beside it. Use the actual SRD plant, not an invented tentacled beast.
DM hex map: Quagmire Beast
Trigger. Pulling the raft’s line attracts its attention to reachable creatures.
Run it. Cutting three visible binding vines from beyond reach with a long hooked tool takes one action each and frees the raft, an original salvage procedure. In combat use actual two-Slam grapple/Engulf requirements, and preserve Lightning Absorption rather than treating lightning as a weakness. It stops pursuing at the dry causeway in this scene.
Resolution and reward. The raft holds 45 gp of trade supplies; returning them earns a 30 gp rescue fee. Retreat leaves the optional salvage behind.
Adjust. Easier: raft is already half free. Harder: its line is tangled under a visible log first.
SRD reference: Shambling Mound
Large plant, unaligned
AC 15 (natural armor) | HP 136 (16d10 + 48) | Speed 20 ft., swim 20 ft. | CR 5 (1,800 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 8 (−1) | 16 (+3) | 5 (−3) | 10 (+0) | 5 (−3) |
- Skills: Stealth +2
- Damage Resistances: cold, fire
- Damage Immunities: lightning
- Condition Immunities: blinded, deafened, exhaustion
- Senses: blindsight 60 ft. (blind beyond this radius), passive Perception 10
- Languages: —
Lightning Absorption. Whenever the shambling mound is subjected to lightning damage, it takes no damage and regains a number of hit points equal to the lightning damage dealt.
Actions
Multiattack. The shambling mound makes two slam attacks. If both attacks hit a Medium or smaller target, the target is grappled (escape DC 14), and the shambling mound uses its Engulf on it.
Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.
Engulf. The shambling mound engulfs a Medium or smaller creature grappled by it. The engulfed target is blinded, restrained, and unable to breathe, and it must succeed on a DC 14 Constitution saving throw at the start of each of the mound’s turns or take 13 (2d8 + 4) bludgeoning damage. If the mound moves, the engulfed target moves with it. The mound can have only one creature engulfed at a time.
11. Swamp Witch’s Choice
At a glance: levels Any | Social / investigation | 20–25 minutes | Creatures: 1 × Commoner.
A hooded seller sets a copper charm on her counter. “Keep the silver payment, or find who lost this. You cannot fairly do both.”
Setup. A 50-foot dry market island has south landing and north path. Herbalist Nessa uses commoner statistics and speaks Common; her “witch” title adds no spellcasting. A posted notice names the charm’s owner at the next village.
DM hex map: Swamp Witch's Choice
Trigger. She offers 10 gp for delivering it, trusting the party to return the owner’s existing 10 gp deposit instead of claiming two payments.
Run it. Examining the charm reveals an ordinary engraved keepsake without a curse. The choice is financial and social, not hidden mind control. Agreeing to delivery receives a written receipt; refusal leaves her willing to sell ordinary rations at 5 sp each, stock four. Threats make her close the stall and leave north.
Resolution and reward. Honest delivery earns one 10 gp fee and a named herbalist contact. Keeping both payments damages that explicit relationship if discovered.
Adjust. Shorter: owner arrives during the discussion. Longer: the owner claims the deposit was larger and the receipt settles it.
SRD reference: Commoner
Medium humanoid (any race), any alignment
AC 10 | HP 4 (1d8) | Speed 30 ft. | CR 0 (10 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) |
- Senses: passive Perception 10
- Languages: any one language (usually Common)
Actions
Club. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 2 (1d4) bludgeoning damage. Commoners include peasants, serfs, slaves, servants, pilgrims, merchants, artisans, and hermits.
12. Poisonous Thicket
At a glance: levels 2–5 | Original hazard / exploration | 15–20 minutes | Creatures: No combat creatures.
Oily leaves lean over the path. A torn glove hangs from a branch beside a scratched warning sign.
Setup. A 40-foot trail has south retreat and a 20-minute west detour. The central 10 feet contain original irritant plants; a hooked pruning tool lies beside the sign. No official spell or monster is being renamed.
DM hex map: Poisonous Thicket
Trigger. Unprotected skin touching the marked leaves requires one DC 12 Constitution save per crossing.
Run it. Failure deals 1d6 poison damage; success deals none. No paralysis, lasting poison condition, or disease is added. Covering exposed skin and pruning with the tool takes 10 minutes and removes the exposure check. A pole can also hold branches aside while others pass. Fire is unnecessary and creates no automatic gas explosion.
Resolution and reward. An old cache beyond the hedge contains 15 gp and a chart of the maintained causeway. The detour reaches it too.
Adjust. Easier: only one branch blocks passage. Harder: carry a supply bundle while keeping it clear of the leaves.
13. Swamp Elemental Convergence
At a glance: levels 5–8 | Repair / combat | 20–30 minutes | Creatures: 1 × Water Elemental.
Water climbs into a turning column. Beneath it, an old wheel shudders against a fallen pole.
Setup. A 70-foot levee has firm south approach and east bypass. One water elemental occupies a 20-foot north pool. Its muddy appearance adds no poison, plant, or earth-elemental traits.
DM hex map: Swamp Elemental Convergence
Trigger. Approaching the wheel reveals its visible obstruction; stepping into the pool draws the creature’s attention.
Run it. Pulling the pole takes an action and DC 13 Athletics, or two actions using a secured rope from the levee. The freed wheel drains the eddy north, and the elemental follows by original behavior. Combat uses actual Whelm and Slam; ordinary mud does not grant extra engulf targets or new immunities.
Resolution and reward. Repair earns 50 gp from nearby farmers and opens the direct levee route. The east bypass takes 40 minutes and stays available.
Adjust. Easier: pole is already tied to a rope. Harder: first unhook a tangled fishing net with an action.
SRD reference: Water Elemental
Large elemental, neutral
AC 14 (natural armor) | HP 114 (12d10 + 48) | Speed 30 ft., swim 90 ft. | CR 5 (1,800 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 14 (+2) | 18 (+4) | 5 (−3) | 10 (+0) | 8 (−1) |
- Damage Resistances: acid; bludgeoning, piercing, and slashing from nonmagical attacks
- Damage Immunities: poison
- Condition Immunities: exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained, unconscious
- Senses: darkvision 60 ft., passive Perception 10
- Languages: Aquan
Water Form. The elemental can enter a hostile creature’s space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.
Freeze. If the elemental takes cold damage, it partially freezes; its speed is reduced by 20 feet until the end of its next turn.
Actions
Multiattack. The elemental makes two slam attacks.
Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.
Whelm (Recharge 4–6). Each creature in the elemental’s space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) bludgeoning damage. If it is Large or smaller, it is also grappled (escape DC 14). Until this grapple ends, the target is restrained and unable to breathe unless it can breathe water. If the saving throw is successful, the target is pushed out of the elemental’s space. The elemental can grapple one Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental’s turns, each target grappled by it takes 13 (2d8 + 4) bludgeoning damage. A creature within 5 feet of the elemental can pull a creature or object out of it by taking an action to make a DC 14 Strength and succeeding.
14. Fungal Infestation
At a glance: levels 2–4 | Combat / containment | 15–25 minutes | Creatures: 2 × Violet Fungus.
Two purple growths lean toward a wooden platform. An empty stone pen stands beside the path.
Setup. A shaded 50-foot island has south landing and east boardwalk. Two violet fungi stand 15 feet apart, 25 feet north. The raised food store can be pulled west with an attached 20-foot rope.
DM hex map: Fungal Infestation
Trigger. Moving near the store starts their slow approach toward the food, original scenario behavior.
Run it. Pulling the store to the dry west side takes two actions and keeps it beyond their 10-foot reach. The fungi use only actual Rotting Touch attacks, including their 1d4 attack count, not poisonous spores. Luring their slow movement into the stone pen and closing its gate with an action contains them without killing them. Keep the gate operator beyond reach.
Resolution and reward. Saving the store earns 4 rations and 15 gp. Bypassing leaves the food at risk but keeps the boardwalk open.
Adjust. Easier: 1 fungus. Harder: move one loose board before the store can slide.
SRD reference: Violet Fungus
Medium plant, unaligned
AC 5 | HP 18 (4d8) | Speed 5 ft. | CR 1/4 (50 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 3 (−4) | 1 (−5) | 10 (+0) | 1 (−5) | 3 (−4) | 1 (−5) |
- Condition Immunities: blinded, deafened, frightened
- Senses: blindsight 30 ft. (blind beyond this radius), passive Perception 6
- Languages: —
False Appearance. While the violet fungus remains motionless, it is indistinguishable from an ordinary fungus.
Actions
Multiattack. The fungus makes 1d4 Rotting Touch attacks.
Rotting Touch. Melee Weapon Attack: +2 to hit, reach 10 ft., one creature. Hit: 4 (1d8) necrotic damage.
15. Marsh Sprite Lanterns
At a glance: levels 1–4 | Social / navigation | 10–20 minutes | Creatures: 2 × Sprite.
Two small winged figures admire lanterns arranged like a smiling face. The boardwalk behind them is dark.
Setup. A 50-foot island has south landing and north boardwalk. Two sprites stand visibly by three hooded lanterns, 10 feet apart. They replace invented witchlight marsh fairies, gaining no unique light powers.
DM hex map: Marsh Sprite Lanterns
Trigger. They ask travelers to guess the picture before returning the lamps.
Run it. A friendly guess or explanation that the route needs marking earns cooperation without a check. Returning each lamp to a visibly matching post takes one action. Threats make them fly east and leave the lanterns behind. No misleading light compels movement into water or automatically charms anyone.
Resolution and reward. Restoration reveals the next three safe posts and a 10 gp silver token dropped beneath one. The sprites identify its owner’s village.
Adjust. Easier: one lamp remains in place. Longer: a traveler arrives who needs the route relit immediately.
SRD reference: Sprite
Tiny fey, neutral good
AC 15 (leather armor) | HP 2 (1d4) | Speed 10 ft., fly 40 ft. | CR 1/4 (50 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 3 (−4) | 18 (+4) | 10 (+0) | 14 (+2) | 13 (+1) | 11 (+0) |
- Skills: Perception +3, Stealth +8
- Senses: passive Perception 13
- Languages: Common, Elvish, Sylvan
Actions
Longsword. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 1 slashing damage.
Shortbow. Ranged Weapon Attack: +6 to hit, range 40/160 ft., one target. Hit: 1 piercing damage, and the target must succeed on a DC 10 Constitution saving throw or become poisoned for 1 minute. If its saving throw result is 5 or lower, the poisoned target falls unconscious for the same duration, or until it takes damage or another creature takes an action to shake it awake.
Heart Sight. The sprite touches a creature and magically knows the creature’s current emotional state. If the target fails a DC 10 Charisma saving throw, the sprite also knows the creature’s alignment. Celestials, fiends, and undead automatically fail the saving throw.
Invisibility. The sprite magically turns invisible until it attacks or casts a spell, or until its concentration ends (as if concentrating on a spell). Any equipment the sprite wears or carries is invisible with it.
16. Murmuring Marsh Spirits
At a glance: levels Any | Social / remembrance | 15–20 minutes | Creatures: No combat creatures.
Whispers repeat three names over the water. A tiny bell lies in the mud beside an empty bracket.
Setup. A 40-foot firm island has south landing and east boardwalk. Original noncombat apparitions stand beyond the north shore; the bell and bracket are safely on land, 10 feet apart.
DM hex map: Murmuring Marsh Spirits
Trigger. Picking up the bell makes the voices pause, indicating the intended task.
Run it. Cleaning and hanging it takes two actions and no check. Reading the visible names, Pela, Dorn, and Is, while ringing it ends the vision. Wrong pronunciation earns a gentle repetition rather than damage. Leaving remains safe. These projections have no ghost, wraith, or possession statistics.
Resolution and reward. The bracket’s inscription permits travelers to take a 20 gp donation purse for emergency supplies and names a safe campsite east.
Adjust. Easier: bell is already clean. Longer: a living family member wants a fourth name added respectfully.
17. Sinkhole Ambush
At a glance: levels 3–5 | Original hazard / combat | 15–25 minutes | Creatures: 2 × Giant Centipede.
A plank bends with a wet crack. Beneath it, many legs scatter across a shallow mud shelf.
Setup. A 50-foot boardwalk has a visibly weak 10-foot center section over a 5-foot-deep depression. Two giant centipedes occupy the shelf below; a firm west bank bypasses it in 10 minutes.
DM hex map: Sinkhole Ambush
Trigger. Putting weight on the weak section breaks it; announce the sag before anyone commits.
Run it. DC 12 Dexterity save returns a traveler to the last sound square; failure lands on the shelf without falling damage. An anchored rope lets a helper pull someone out with an action. Centipedes attack only creatures beside them, using their actual poison and special 0-HP effect, then flee into cracks when one dies. No automatic surprise attacks accompany the fall.
Resolution and reward. A dropped 15 gp tool bag can be hooked from the sound bank. Repairing the plank prevents recurrence for later travelers.
Adjust. Easier: a rope already spans the break. Harder: replace two loose planks before crossing.
SRD reference: Giant Centipede
Small beast, unaligned
AC 13 (natural armor) | HP 4 (1d6 + 1) | Speed 30 ft., climb 30 ft. | CR 1/4 (50 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 5 (−3) | 14 (+2) | 12 (+1) | 1 (−5) | 7 (−2) | 3 (−4) |
- Senses: blindsight 30 ft., passive Perception 8
- Languages: —
Actions
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 4 (1d4 + 2) piercing damage, and the target must succeed on a DC 11 Constitution saving throw or take 10 (3d6) poison damage. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way.
18. Swamp Druid’s Challenge
At a glance: levels 2–5 | Social / restoration | 15–25 minutes | Creatures: 1 × Druid.
A robed figure points to stranded fish beside a blocked channel. “Open a road for them before you ask one for yourselves.”
Setup. A 60-foot dry levee has south approach and east passage. One druid stands by a shallow channel blocked with three loose boards. The boards are reachable from dry ground, 10 feet apart.
DM hex map: Swamp Druid's Challenge
Trigger. The keeper offers a map after the channel is reopened.
Run it. Removing each board takes one adjacent action; if a board is jammed, DC 12 Strength frees it immediately or two actions with a lever guarantees it. The fish escape once all three are removed. There is no mandatory spell duel or punitive curse for failure. Refusal leaves a 30-minute public detour open.
Resolution and reward. Help earns the map of the next two sluices and 4 rations. The keeper can watch the party’s camp while they rest afterward.
Adjust. Easier: only one board remains. Longer: an arriving farmer fears losing irrigation water and needs a compromise.
SRD reference: Druid
Medium humanoid (any race), any alignment
AC 11 (16 with barkskin) | HP 27 (5d8 + 5) | Speed 30 ft. | CR 2 (450 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 12 (+1) | 13 (+1) | 12 (+1) | 15 (+2) | 11 (+0) |
- Skills: Medicine +4, Nature +3, Perception +4
- Senses: passive Perception 14
- Languages: Druidic plus any two languages
Spellcasting. The druid is a 4th–level spellcaster. Its spellcasting ability is Wisdom (spell save DC 12, +4 to hit with spell attacks). It has the following druid spells prepared: Cantrips (at will): druidcraft, produce flame, shillelagh 1st level (4 slots): entangle, longstrider, speak with animals, thunderwave 2nd level (3 slots): animal messenger, barkskin
Actions
Quarterstaff. Melee Weapon Attack: +2 to hit (+4 to hit with shillelagh), reach 5 ft., one target. Hit: 3 (1d6) bludgeoning damage, 4 (1d8) bludgeoning damage if wielded with two hands, or 6 (1d8 + 2) bludgeoning damage with shillelagh. Druids dwell in forests and other secluded wilderness locations, where they protect the natural world from monsters and the encroachment of civilization. Some are tribal shamans who heal the sick, pray to animal spirits, and provide spiritual guidance.
19. Abandoned Swamp Village
At a glance: levels 3–5 | Combat / investigation | 20–30 minutes | Creatures: 3 × Zombie.
Doors hang open above shallow water. Three figures stand around a sealed chest on the raised meeting platform.
Setup. A 60-foot square has south landing and east boardwalk. Three zombies stand 25 feet north in 2-foot water; the platform is reachable by a dry west plank. They gain no swimming speed or new disease attack.
DM hex map: Abandoned Swamp Village
Trigger. Moving the chest or entering within 5 feet of a zombie starts initiative.
Run it. Using the west plank to loop a rope around the chest permits hauling it south with two actions without approaching the watchers. If fighting, use actual Slam and Undead Fortitude; radiant damage and critical hits retain their printed effects on that trait. Zombies pursue only inside the village square.
Resolution and reward. The unlocked chest holds 30 gp and a flood register identifying where surviving villagers moved. This provides a concrete destination rather than an undefined curse quest.
Adjust. Easier: 2 zombies. Harder: the rope must be passed around a post before hauling.
SRD reference: Zombie
Medium undead, neutral evil
AC 8 | HP 22 (3d8 + 9) | Speed 20 ft. | CR 1/4 (50 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 13 (+1) | 6 (−2) | 16 (+3) | 3 (−4) | 6 (−2) | 5 (−3) |
- Saving Throws: Wis +0
- Damage Immunities: poison
- Condition Immunities: poisoned
- Senses: darkvision 60 ft., passive Perception 8
- Languages: understands the languages it knew in life but can’t speak
Undead Fortitude. If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point instead.
Actions
Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.
20. Marsh Marauders
At a glance: levels 3–5 | Social / combat | 20–25 minutes | Creatures: 3 × Bandit.
Three figures lean on poles across the landing. Their canoe is piled with goods bearing several different owner marks.
Setup. A 50-foot dock has south water approach and east boardwalk. Three bandits stand openly 25 feet ahead. Their amphibious reputation adds no water breathing or swimming speed; they use an ordinary canoe.
DM hex map: Marsh Marauders
Trigger. They demand 5 gp or one food crate for passage.
Run it. Payment ends the demand. Showing that the landing’s plaque names it public and succeeding on DC 12 Persuasion persuades them to back down; failure leaves a 20-minute alternate landing west. In combat they use actual weapons and flee by canoe after one falls. They do not sink the party’s boat through narration.
Resolution and reward. Their cargo tags identify two robbed traders; returning tags earns a 20 gp reward. Recovered coins total 18 gp.
Adjust. Easier: 2 bandits. Longer: one trader arrives during negotiations to identify their goods.
SRD reference: Bandit
Medium humanoid (any race), any non–lawful alignment
AC 12 (leather armor) | HP 11 (2d8 + 2) | Speed 30 ft. | CR 1/8 (25 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 11 (+0) | 12 (+1) | 12 (+1) | 10 (+0) | 10 (+0) | 10 (+0) |
- Senses: passive Perception 10
- Languages: any one language (usually Common)
Actions
Scimitar. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) slashing damage.
Light Crossbow. Ranged Weapon Attack: +3 to hit, range 80 ft./320 ft., one target. Hit: 5 (1d8 + 1) piercing damage. Bandits rove in gangs and are sometimes led by thugs, veterans, or spellcasters. Not all bandits are evil. Oppression, drought, disease, or famine can often drive otherwise honest folk to a life of banditry.
Pirates are bandits of the high seas. They might be freebooters interested only in treasure and murder, or they might be privateers sanctioned by the crown to attack and plunder an enemy nation’s vessels.
21. Swamp Fever Outbreak
At a glance: levels Any | Investigation / aid | 20–30 minutes | Creatures: 3 × Commoner.
Three weary travelers sit beside a green water jar. A clean spring runs beyond a broken fence.
Setup. A 60-foot dry camp has south trail and east spring, 30 feet away. Three commoners are ill but stable. This is an original noncontagious waterborne scene; visiting or talking causes no disease check.
DM hex map: Swamp Fever Outbreak
Trigger. They ask for clean water and help marking the unsafe pool.
Run it. Moving two clean containers to the spring and back takes two actions each. Boiling and cooling the fresh supply takes 20 minutes; a clear warning sign takes 5 minutes. These tasks stabilize the camp’s access to safe water, not magically cure every illness. A DC 12 Medicine check identifies signs requiring a healer; failure still leaves the obvious water replacement plan available.
Resolution and reward. The camp offers 15 gp and the location of a healer 1 hour east. Transporting them there resolves recovery during the journey without a hidden infection roll.
Adjust. Easier: spare water is already in the party’s supplies. Longer: organize a carrying stretcher for the weakest traveler.
SRD reference: Commoner
Medium humanoid (any race), any alignment
AC 10 | HP 4 (1d8) | Speed 30 ft. | CR 0 (10 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) |
- Senses: passive Perception 10
- Languages: any one language (usually Common)
Actions
Club. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 2 (1d4) bludgeoning damage. Commoners include peasants, serfs, slaves, servants, pilgrims, merchants, artisans, and hermits.
Free Rules Sources and Attribution
Creature references reproduce the stat blocks in the Creative Commons edition of SRD 5.1, with formatting and PDF typography normalized; optional variants are omitted unless a scene calls for them. Source links point to the beginning of each block; some continue onto the next page. Scene dialogue, named NPCs, terrain, goals, suggested levels, checks, timers, rewards, and peaceful resolutions are original encounter design. Descriptive creature changes do not add abilities. Rules use the 2014-compatible SRD 5.1 throughout; official SRD downloads also list other versions.
This work includes material taken from the System Reference Document 5.1 (“SRD 5.1”) by Wizards of the Coast LLC and available at https://dnd.wizards.com/resources/systems-reference-document. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available at https://creativecommons.org/licenses/by/4.0/legalcode.