Sphere of Crushing Doom

TrapXGEp. 1192014

The court jester devised a deadly trap to foil anyone who sought to steal his magic fool's cap. The jester's tomb is located at the end of a 10-foot-wide, 150-foot-long hallway that descends sharply from north to south. The entrance to the tomb is a door on the eastern wall at the bottom of the slope, at the south end of the hall.

Raw data
{
  "name": "Sphere of Crushing Doom",
  "page": 119,
  "__prop": "trap",
  "rating": [
    {
      "tier": 2,
      "threat": "deadly"
    }
  ],
  "source": "XGE",
  "eActive": [
    "Although the trap is complex in nature, it has a single active element. That's all it needs.",
    {
      "type": "list",
      "items": [
        {
          "name": "Sphere of Crushing Doom (Initiative 10)",
          "type": "item",
          "entry": "The trap's active element is a sphere of steel that almost fills the 10-foot width of the hallway and rolls to the bottom of the slope on its turn. Each creature in the sphere's path must make a {@dc 20} Strength saving throw. On a failed save, a creature takes 22 ({@damage 4d10}) bludgeoning damage and is knocked {@condition prone}. On a successful save, a creature takes half as much damage and isn't knocked {@condition prone}. Objects that block the sphere, such as a conjured wall, take maximum damage from the impact."
        }
      ],
      "style": "list-hang-notitle"
    }
  ],
  "entries": [
    "The court jester devised a deadly trap to foil anyone who sought to steal his magic fool's cap. The jester's tomb is located at the end of a 10-foot-wide, 150-foot-long hallway that descends sharply from north to south. The entrance to the tomb is a door on the eastern wall at the bottom of the slope, at the south end of the hall."
  ],
  "trigger": [
    "This trap activates as soon as the door leading to the jester's coffin is opened. A magic portal opens at the northern end of the hallway and disgorges an enormous steel sphere, which hurtles down the slope. When it reaches the bottom of the slope, a second portal briefly appears and teleports the sphere back to the top of the slope to begin the process again."
  ],
  "eDynamic": [
    "The longer it rolls, the more lethal the sphere becomes.",
    {
      "type": "list",
      "items": [
        {
          "name": "Speed Kills",
          "type": "item",
          "entry": "After its turn, the sphere gains speed, represented by its damage increasing by 11 ({@damage 2d10}). While its damage is 55 ({@damage 10d10}) or greater, it acts on initiative count 20 and 10."
        }
      ],
      "style": "list-hang-notitle"
    }
  ],
  "initiative": 1,
  "trapHazType": "CMPX",
  "initiativeNote": "but see the dynamic element below",
  "countermeasures": [
    "The trap can be neutralized either by stopping the sphere or preventing it from teleporting.",
    {
      "type": "list",
      "items": [
        {
          "name": "Stop the Sphere",
          "type": "item",
          "entry": "Stopping the sphere is the easiest way to disrupt the trap. A wall of force can do so easily, as can any object placed in its path that has enough hit points to absorb damage from the sphere without being destroyed."
        },
        {
          "name": "Disrupt the Portals",
          "type": "item",
          "entries": [
            "Either portal can be neutralized with three successful {@dc 20} Intelligence ({@skill Arcana}) checks, but the process of analyzing a portal to disrupt it takes time. Faint runes in the ceiling and floor at both ends of the hallway are involved in the functioning of the portals. A creature must first use an action to examine a set of runes, then use a subsequent action to attempt to vandalize the runes. Each successful check reduces the sphere's damage by 11 ({@damage 2d10}), as the disrupted sphere loses speed moving through the failing portal.",
            "Alternatively, a set of runes can be disabled with three successful castings of {@spell dispel magic} ({@dc 19}) targeting any of the runes in the set.",
            "If the southern portal is destroyed, the sphere slams into the south wall and comes to a halt. It blocks the door to the tomb, but the characters can escape."
          ]
        }
      ],
      "style": "list-hang-notitle"
    }
  ]
}