A body lies motionless in the mud beside the small hut, half-covered in rotting moss. Its stomach has split open, as if something forced its way out from within. The air hangs thick with the stench of decay and wet earth.

Nearby, the corpse of a great boar slumps in the mud. Its hide is carpeted in slick green moss and dotted with tiny red flowers swaying gently in the marsh breeze.

The hut itself is little more than a hunter’s shelter, barely large enough for one person to sleep inside. A longbow and a few arrows hang neatly on the wall beside several coiled snares. A half-tanned boar hide stretches across a wooden frame, and several snake skins hang from the rafters, stirring faintly in the damp air.

The body belongs to Toran Kester, who was infected by the Corpse Bloom Fungus, the same strain that originated from the crocodile the players encountered earlier (Clue 2).

The great boar nearby was infected soon after, likely when Toran’s corpse burst in a cloud of spores.

Encounter Setup

• If the players inspect the boar, fungal tendrils will suddenly sprout from its moss-covered hide, attacking any creature within 10 feet.

• The boar’s body is bloated and unstable—it could explode at any moment.

• Once the encounter begins, roll 1d4 + 1 (2–5 rounds) to determine how many rounds remain before the boar bursts in a Death Burst of spores.

• If the boar is killed before that time, it also explodes immediately, triggering the Death Burst effect (see Corpse Bloom Fungus stat block).

Investigation Details

• Toran’s Body: Safe to touch. The moss is dead and rotting.

• Boar’s Body: Still infectious — contact triggers “Sticky Moss” (see Corpse Bloom Fungus traits).

• A successful DC 13 Medicine or Nature check reveals both corpses show signs of the same parasitic infection.

Loot & Clues Inside the Hut

Inside the small hunting hut, the party finds:

• 1 Giant Constrictor Snake Skin – 20 gp value (especially to Kester’s Leathers)

• 1 Giant Boar Hide - 20 gp

• 2 Constrictor Snake Skins – 10 gp each

• 1 Longbow

• 4 Snare Traps

• 1 Quiver of Arrows

Reward:
If the players return the longbow, quiver, and snake hides to Kester’s Leathers, they receive an appropriate reward or favor from the Kester family.

Aftermath & Consequences

If the players report their findings to Captain Eliander Fireborn:

• He becomes deeply concerned about the potential spread of the infection.

• Within a day, he orders the Drowned Forest closed to hunters.

• Anyone returning from the forest must be quarantined for a day and treated by Marella (the Sea Herbalist) with her Snail Elixir and Pearl Infusion before re-entering Saltmarsh.

• A public notice is posted at the city gate warning of the “marsh plague.”

Ongoing Hooks

Consider how the Corpse Bloom Fungus could evolve into a larger threat to Saltmarsh, Burle, or the surrounding wilderness.

• Is the infection spreading through animals, smugglers, or river trade?

• Could a cult or Keledek’s experiments connect to its origin?

• The next outbreak might not be confined to the swamp.

Lore

Over the next day, the infected corpse’s skin takes on a waxy green hue and within a day turns into a wet moss carpet over the flesh. From this moss, tiny red flowers bloom.

Inside the corpse fibrous tendrils (up to eight) have grown and will sprout from the body if threatened.

The tendrils, capable of stretching ten feet, flail protectively around the corpse as the fungus matures.

Within 1d4+1 (2-5) days, the host’s organs swell grotesquely from trapped gases and growing spores. When mature, the fungus erupts outward, showering the area in viscera and infectious spores that spread within a 20-30 foot radius.

Local hunters whisper that “the moss from the Hool Marsh can devour creatures,” and that any bloated carcass found in the marsh should be burned immediately.

It is said to be found only in the deep Hool Marsh. If found in the Drowned Forest, it could spread quickly and become a problem for Saltmarsh.

Infection

A creature exposed to the spores must make a DC 12 Constitution saving throw or become infected. (see Death Burst)

• On infection, the victim suffers 1 level of exhaustion, and their veins darken to a black-blue hue.

• Each dawn, the victim must repeat the saving throw, the DC increasing by +1 each day (DC 13, 14, 15, etc.).

• On a failed save, the victim gains one additional level of exhaustion.

• While infected, the victim regains hit points during rests at disadvantage on Hit Die rolls, taking the lower result and on a Long Rest can only gain 50% of their max Hit Points. Exhaustion is not reduced by Long Rest.

If the infection is not cured, the victim dies when they reach 6 levels of exhaustion.
After death, tendrils sprout from the corpse’s eyes, mouth, and abdomen, growing up to 10 feet long. Within 1d4+1 days, the body bursts, spreading spores within a 20-30 foot radius.

Cure

Marella the Sea Herbalist (of Sharkfin Bridge) knows how to concoct a cure: a mixture of Snail Elixir and Pearl Infusion that neutralizes the fungal spores within the bloodstream. A successful DC 14 Medicine or Herbalism Kit check using these ingredients removes the infection.

Corpse Bloom Fungus

Large Plant, Unaligned
Armor Class 8
Hit Points 19 (3d10 + 3)
Speed 5 ft., reach 10 ft. (tendrils)

Condition Immunities Blinded, Charmed, Deafened, Frightened, Paralyzed, Poisoned, Prone
Damage Immunities Poison
Vulnerabilities Fire
Senses Blindsight 30 ft. (blind beyond), Passive Perception 8
Languages —
Challenge 1 (200 XP)
Proficiency Bonus +2

Traits

Death Burst.

When the Corpse Bloom Fungus dies, it releases a toxic cloud of spores.

• If destroyed prematurely (by any means but fire): The cloud expands in a 20-foot radius, as the fungus ruptures before reaching full maturity.

• If allowed to mature and burst naturally: The explosion is far more violent, spreading spores in a 30-foot radius.

Each creature in that area must make a DC 12 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much on success. On a failure, the creature also becomes infected (see Infection ).

Note. If the Corpse Bloom Fungus is burned before it reaches maturity, it will not trigger its Death Burst, and all spores are destroyed. Fire damage completely incinerates the fungus and prevents further infection or spore spread.

Sticky Moss.
The mossy layer is highly toxic. Any creature that touches or walks on it must succeed on a DC 10 Constitution saving throw or be poisoned for 1d12 hours.

Tendril Flail.
The tendrils normally remain hidden within the corpse, but when threatened or approached, they whip outward to defend it. The corpse’s moss-covered tendrils lash autonomously at nearby creatures. Each tendril has 5 hit points, and the Corpse Bloom Fungus has eight tendrils in total.

Multiattack.
The Corpse Bloom Fungus makes two Tendril attacks.

Actions

Tendril. Melee Weapon Attack: +2 to hit, reach 10 ft., one target.
Hit: 5 (2d4) poison damage, and the target must succeed on a DC 12 Constitution saving throw or be poisoned until the end of its next turn.