Trap: Miasmic Quagmire Trap

Adam Pate

March 7, 2025

Trap

Miasmic Quagmire Trap

Complexity: Complex

Type: Environmental/Hybrid

Severity: Dangerous

Trigger: Weight compresses the surface of the swamp

Effect: DC 13 Constitution saving throw; Failure: 2d10 poison damage and Poisoned condition for 1 minute; Success: Half damage, no adverse effects; Secondary effects apply for continued Poisoned condition.

Damage Output: Initial damage of 2d10 poison damage, 1d10 poison damage for sustained poisoning. (Poison)

Detection DC: DC 12 Perception or Nature check to detect signs of danger

Disarm DC: Nature/Survival Check (DC 15) to find a safe path, Performance Check (DC 14) to create a distraction.

The Miasmic Quagmire presents itself as an eerily serene expanse of muddy ground—a trap disguised amidst the haze of the swamp. The ground is slick and seemingly solid, dotted with patches of vibrant greenery that contrast sharply against the dull brown muck. As characters step onto the quagmire, it ripples ominously beneath them, the air thickening with the stench of decay and damp earth. An unsettling gurgle erupts as swathes of poisonous vapor burst forth, swirling about in a nasty miasma that clings to the skin, heavy and acrid. Those caught within face not only the pain of noxious fumes but also the debilitating effects that weaken their resolve, drawing them deeper into the swamp’s treacherous embrace.

Gameplay Notes for Miasmic Quagmire Trap

Trap Activation

Trigger Mechanism: The trap is activated when characters step onto an area of the quagmire, disturbing the top layer of mud. Once a character steps on this patch, the poisonous spores become agitated.
Activation Condition: The trap will activate when a player character (PC) of Medium size or larger steps onto the unstable ground, causing enough weight pressure to trigger the bubbling and toxic explosion of the miasma.

Detection and Disarm Notes

Detection Clues:
- Perception or Nature Checks (DC 12): Success reveals subtle clues like vibrant flora, buzzing insects, or faint gurgling sounds from the muck. A character might identify that the area is unstable.
Post-Activation Disarm Attempts:
- Naturalist’s Navigation (Nature or Survival check, DC 15): Allows a player to find a safer path through the quagmire, reducing poison damage.
- Distraction (Performance check, DC 14): Creates a diversion to minimize the radius of the poisonous effect.

Suggested Tactics and Variations

Targeting: The trap can visually “target” the character closest to the quagmire after it activates, concentrating the cloud effect directly around them. Additionally, if players attempt to run away or retreat, the trap can respond by expanding its radius, forcing them to make checks to avoid further exposure.
Environmental Flavor: Pitch in descriptions such as “The air thickens, and the sounds of the swamp seem to quiet, as if the creatures are wary of the foul brew beneath your feet.”
Increasing Challenge: Introduce additional hazards based on the party’s actions (e.g., if players loudly yell, it can draw swamp creatures, or a sudden storm might worsen the quagmire).

Initiative and Round Actions

Initiative: The Miasmic Quagmire uses a +2 initiative modifier, rolling 1d20 + 2. It acts in the order based on the total rolled.
Trap Actions Per Round: The trap operates over a series of rounds, each corresponding to the players’ turns in initiative order:
- Round 1: Initial activation and effect
  - Each affected character must make a DC 13 Constitution saving throw or take 2d10 poison damage and suffer the Poisoned condition for 1 minute.
- Round 2: Toxic miasma spreads
  - Each character within 10 feet must make another DC 13 Constitution saving throw (this is separate from the initial). On a failure, they take an additional 1d10 poison damage. The radius of the toxicity effect starts to increase to 15 feet, affecting new characters who move in.
- Round 3: Evolving conditions
  - The quagmire grows thicker, and the toxic fog now impairs vision. Characters not currently affected by the Poisoned condition must succeed on a DC 13 Wisdom saving throw or become frightened for 1 minute as they inhale the noxious vapors.
- Subsequent Rounds:
  - On every turn thereafter, characters suffering the Poisoned condition take 1d10 poison damage at the start of their turn if they fail the ongoing DC 13 Constitution check to shake it off.

Round-by-Round Effects

Phase 1 (Round 1):
- Activation: Upon triggering, each character within the area must roll the initial saving throw for poison damage.
Phase 2 (Rounds 2-3):
- Round 2: Radius increases, random damage triggered with a new saving throw.
- Round 3: Fog-induced fear activated among those who are not affected, causing hesitation or further complications in navigating the area.
Phase 3 (Ongoing):
- As rounds continue, if at least one character is Poisoned, damage persists, and environmental conditions (smaller creatures emerging from the muck, stronger winds, etc.) worsen, complicating further movement and actions.

Additional Tips for Running the Trap

Visual Aids: Use visual aids to show players how the quagmire looks and evolves. Consider drawing the changing radius or using markers to indicate transitions as conditions worsen.
Encourage Teamwork: Encourage players to strategize ways to navigate or assist each other in minimizing the effects, fostering collaboration.
Narrative-Driven Responses: Use narrative flair to emphasize how the swamp reacts to various actions to create tension and enhance immersion.
Maintaining Flow: Track conditions and damage effects carefully to ensure the pace feels dynamic and keeps tension high without cumbersome management. Utilize notes or markers to organize ongoing effects.

By managing the Miasmic Quagmire’s mechanics and escalating dangers effectively, the Dungeon Master can create a multi-faceted challenge that immerses players in the swamp’s hazardous environment.

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