The Overgrown Forges
One-Page Dungeons: The Overgrown Forges
1. The Sighing Pistons
Level Range & Gimmick: Levels 4–6. The Hallucinogenic Venting. The industrial bellows of Steamfort no longer pump air, but a concentrated mixture of geothermal steam and Mycelia-Zul spores. Every 1d4 rounds, a random brass valve in the room bursts. All non-fungal creatures must succeed on a DC 14 Constitution save or increase their Spore Infection Tier by one. While affected by the "Hallucinogenic Paranoia" of this sector, players perceive their own allies as hostile Spore-Cougher Swarms, requiring a DC 15 Wisdom save to take any action other than "Attack" or "Dodge."
Tactical Challenge: Kinetic Heat-Grids. The floor consists of shifting brass plates. At the start of each round, a "Heat Pattern" emerges: 30% of the tiles become glowing red (dealing 2d10 fire damage), 30% become "Overgrown" with slick, blue-green mycelium (Difficult Terrain), and the rest remain safe. Combatants must use shove actions and forced movement to push enemies into the heat zones while avoiding the grasping, vine-choked machinery that attempts to Grapple anyone standing on an Overgrown tile.
The Loot: Huge Throbbing Treasure. Contains the Pulse-Core Gauntlet, a heavy dwarven prosthetic fused with a living fungal heart. The wearer can expend their own "Infection Tiers" to unleash a 30ft cone of concussive force (1d12 per tier expended). Also includes 2,200gp in tarnished dwarven bullion.
2. Thordin’s Hallucinogenic Crucible
Level Range & Gimmick: Levels 5–7. The Pressure Lockout. The chamber is a vertical forge-shaft where High Forge-Master Thordin is physically grafted into the central machinery. To reach him, players must manipulate three "Steam-Siphon" levers located on high, unstable gantries. For every round the levers aren't balanced, the room's "Toxicity Gauge" rises. At max pressure, the forge triggers a Scrubbing Flash—a burst of boiling alchemical waste that deals 4d8 Acid damage to everything in the room, clearing the fungus but potentially killing the party.
Tactical Challenge: Living Mycelial Bridges. There are no stairs, only pulsating, translucent fungal bridges connecting the rusted dwarven walkways. These bridges are part of the hive-mind; they have 30 HP and an AC of 10. If a bridge takes damage, it "flinches," forcing everyone on it to make a DC 16 Dexterity save or fall into the vat of toxic slag below (6d6 fire/acid damage). Mycelial Stalkers hide underneath these bridges, reaching through the porous fungus to pull players through the floor.
The Loot: Huge Throbbing Treasure. Contains the Calyx of the First Spawning, a crystalline bulb recovered from Thordin's chest. Once per day, it can be shattered to "Sever" any goblin or infected creature within 60ft from Mycelia-Zul's hive-mind, stunning them for 1 minute as they experience individual consciousness for the first time. Also contains 4,500gp in raw azure-crusted mithril shards.