Supercharged Metal Cube
Multiple arcs of lightning connect a 10-foot-tall metal cube to a wall-mounted sword and a brazier. A creature or metal object that moves within 30 feet of the contraption on its turn or starts its turn there triggers a Failure.
Cube. An Engineering or Investigation check, or an examination of the cube, reveals that it is riveted together. Examining the cube from above reveals a trapdoor on the top face of the cube.
The cube is a nonmagical object with AC 17, 100 hit points, and immunity to poison and psychic damage. Disintegrate destroys it. Damaging the cube without destroying it outright triggers a Critical Failure.
Lightning. A Perception check, or an examination of the objects connected by arcs of lightning, reveals that all the objects are made of metal. A metal object thrown within 30 feet of the cube becomes connected to the cube by an arc of lightning.
Arcs of lightning can be blocked by non-metal objects. A creature can approach the cube safely if protected by an object made of stone, wood, or similar material that is at least 1 inch thick.
Sword. At the Narrator’s discretion, the sword may be a magic weapon, such as a flame tongue sword that deals lightning instead of fire damage.
- A creature that can get close enough to the cube can attempt a thieves’ tools check to remove a panel from the side of the cube. The trapdoor in the top of the cube can be opened without a check. In either case, a floating, glowing mote of elemental lightning is revealed, set into a slot within the cube. Touching the mote (either directly or with a metal object) triggers a Failure. A creature that pries out the mote with a non-conductive object, such as a wooden stake, or that triggers a Failure and succeeds on their saving throw , can remove the mote from the slot. Removing it from the slot disables the trap. Once removed, the mote can be attuned to, in which case it functions as a wand of lightning bolts .
Potential Outcomes
Critical Failure. Each creature and metal object within 60 feet of the cube is subjected to a Failure.
Failure. Lightning arcs to the triggering object or creature. If it is an object, it takes no damage but any creature that touches it triggers a failure. If it is a creature, it makes a Constitution saving throw , taking 63 (18d6) lightning damage on a failed save or half damage on a success. Also on a failed save, a creature is pushed 30 feet away from the cube and knocked prone . The lightning does not go around corners.
Success or Critical Success. The trap isn’t triggered.