Obsidian Tendrils Trap
A foot-wide, foot-tall obsidian bridge spans a pool of bubbling lava.
A creature triggers a Failure each time it enters a 5-foot space above the lava on its turn. This includes any space up to 50 feet above the lava, as well as the area of the obsidian bridge.
Lava. The lava bubbles and ripples as if stirred from within. A creature that enters a space within 5 feet of the lava or starts its turn there takes 55 (10d10) ongoing fire damage. An Investigation or Perception check, or observing the pool for 1 minute, reveals black tendrils that occasionally emerge from the surface of the lava.
Dealing at least 50 cold damage to the pool in a single turn causes a 5-foot-square area of the lava to harden into solid obsidian for 1 minute, during which time that area is safe to traverse.
The Narrator determines the size of the pool, but it should be at least 30 feet on a side and offer no obvious route around it. The larger the pool, the more difficult the challenge.
Magical Effect. This is a magical effect created by transmutation magic. Casting dispel magic on the lava requires a spellcasting ability check and dispels the effect on a 5-foot-square area of lava.
- An Acrobatics or Athletics check allows a creature to move or fly above the lava at half its speed without triggering Failures until the end of its turn.
- As an action, a creature can make an Investigation, Nature, or Perception check to watch the surface of the lava. On a success, the creature identifies a safe route across the pool. Until the start of its next turn, the creature can use its reaction to grant itself or a creature that can hear it a Critical Success against the trap.
- A creature can take the Ready action to ready a melee attack against an obsidian tendril. The first time before the start of the creature’s next turn that it makes a Strength saving throw against an obsidian tendril, it can use its reaction to make a melee attack against the vine (AC 18). On a hit, the creature triggers a Success. On a failure, the creature must make the saving throw as normal.
Potential Outcomes
Critical Failure. As a Failure, but the creature makes the Strength saving throw to avoid the obsidian tendril with disadvantage .
Failure. A jagged tendril made of animated obsidian emerges from the lava to grasp the creature. The creature makes a Strength saving throw . On a failure, it takes 11 (2d10) slashing damage and is restrained . The tendril then pulls the restrained creature to within 5 feet of the lava. A creature can use an action to make a Strength check, freeing a restrained creature on a success. The tendrils are objects with AC 18, 50 hit points, and immunity to fire, poison, and psychic damage. Once a tendril has been destroyed, moving into the 5-foot-square area it guards no longer triggers a Failure.
Success. The creature avoids the tendril.
Critical Success. The creature avoids the tendril and automatically succeeds on Strength saving throws against this trap until the end of its turn.