Traps

by Purius

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Traps
A Collection of Obstacles & Death Traps

Table of Contents














Version 1.0

Mechanical Traps

Simple

Bear Trap

Mechanical trap

A bear trap resembles a set of iron jaws that springs shut when stepped on, clamping down on a creature’s leg. The trap is spiked in the ground, leaving the victim immobilized.

Trigger. A creature that steps on the bear trap triggers it.

Effect. The trap makes an attack against the triggering creature. The attack has a +8 attack bonus and deals 5 (1d10) piercing damage on a hit. This attack can’t gain advantage or disadvantage. A creature hit by the trap has its speed reduced to 0. It can’t move until it breaks free of the trap, which requires a successful DC 15 Strength check by the creature or another creature adjacent to the trap.

Countermeasures. A successful DC 10 Wisdom (Perception) check reveals the trap. A successful DC 10 Dexterity check using thieves’ tools disables it.

Collapsing Roof

Mechanical trap

The ceiling is in bad repair, and anyone who can see it can tell that it’s in danger of collapse.

Trigger. This trap uses a trip wire to collapse the supports keeping an unstable section of a ceiling in place.

Effect. When the trap is triggered, the unstable ceiling collapses. Any creature in the area beneath the unstable section must succeed on a DC 15 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one. Once the trap is triggered, the floor of the area is filled with rubble and becomes difficult terrain.

Countermeasures. Anyone who inspects the beams can easily determine that they are merely wedged in place. As an action, a character can knock over a beam, causing the trap to trigger.

The trip wire is 3 inches off the ground and stretches between two support beams. The DC to spot the trip wire is 10. A successful DC 15 Dexterity check using thieves’ tools disables the trip wire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Crossbow Trap

Mechanical trap

The crossbow trap is a favorite of kobolds and other creatures that rely on traps to defend their lairs. It consists of a trip wire strung across a hallway and connected to a pair of hidden heavy crossbows. The crossbows are aimed to fire down the hallway at anyone who disturbs the trip wire.

Trigger. A creature that walks through the trip wire triggers the trap.

Effect. The trap makes two attacks against the triggering creature. Each attack has a +8 attack bonus and deals 5 (1d10) piercing damage on a hit. This attack can’t gain advantage or disadvantage.

Countermeasures. A successful DC 15 Wisdom (Perception) check reveals the trip wire. A successful DC 15 Dexterity check using thieves’ tools disables the trip wire, and a check with a total of 5 or lower triggers the trap.

Falling Portcullis

Mechanical trap

Some folk who build dungeons, such as mad wizards in search of new victims, have no intention of allowing their visitors to make an easy escape. A falling portcullis trap can be especially devious if it causes a portcullis to drop some distance away from the pressure plate that activates the trap. Although the trap is deep in the dungeon, the portcullis closes off the dungeon entrance, which is hundreds of feet away, meaning that adventurers don’t know they are trapped until they decide to head for the exit.

Trigger. A creature that steps on the pressure plate triggers the trap.

Effect. An iron portcullis drops from the ceiling, blocking an exit or a passageway.

Countermeasures. A successful DC 20 Wisdom (Perception) check reveals the pressure plate. A successful DC 20 Dexterity check using thieves’ tools disables it, and a check with a total of 5 or lower triggers the trap.

Falling Net

Mechanical trap

Trigger. This trap uses a trip wire to release a net suspended from the ceiling.

Effect. When the trap is triggered, the net is released, covering a 10-foot-square area. Those in the area are trapped under the net and restrained, and those that fail a DC 10 Strength saving throw are also knocked prone. A creature can use its action to make a DC 10 Strength check, freeing itself or another creature within its reach on a success. The net has AC 10 and 20 hit points. Dealing 5 slashing damage to the net (AC 10) destroys a 5-foot-square section of it, freeing any creature trapped in that section.

Countermeasures. The trip wire is 3 inches off the ground and stretches between two columns or trees. The net is hidden by cobwebs or foliage. The DC to spot the trip wire and net is 10. A successful DC 15 Dexterity check using thieves’ tools breaks the trip wire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Net Trap

Mechanical trap

Goblins, with their propensity to enslave their enemies, prefer traps that leave intruders intact so the victims can be put to work in the mines or elsewhere.

Trigger. A trip wire strung across a hallway is rigged to a large net. If the trip wire is broken, the net falls on intruders. An iron bell is also rigged to the trip wire. It rings when the trap activates, alerting nearby guards.

Effect. A net covering a 10-foot-by-10-foot area centered on the trip wire falls to the floor as a bell rings. Any creature fully within this area must succeed on a DC 15 Dexterity saving throw or be restrained. A creature can use its action to make a DC 10 Strength check to try to free itself or another creature in the net. Dealing 5 slashing damage to the net (AC 10, 20 hp) also frees a creature without harming the creature.

Countermeasures. A successful DC 15 Wisdom (Perception) check reveals the trip wire and the net. A successful DC 15 Dexterity check using thieves’ tools disables the trip wire without causing the net to drop or the bell to ring; failing the check causes the trap to activate.

Pit, Simple

Mechanical trap

The simplest of pit traps consists of a 10-foot-deep hole in the floor, concealed by tattered canvas that’s covered with leaves and dirt to look like solid ground. This type of trap is useful for blocking off the entrance to a monster lair, and usually has narrow ledges along its sides to allow for movement around it.

Trigger. Anyone who steps on the canvas might fall into the pit.

Effect. The triggering creature must make a DC 10 Dexterity saving throw. On a successful save, the creature catches itself on the pit’s edge or instinctively steps back. On a failed save, the creature falls into the pit and takes 3 (1d6) bludgeoning damage from the fall.

Countermeasures. A successful DC 10 Wisdom (Perception) check reveals the presence of the canvas and the 1-foot-wide ledge around the edges of the pit where it is safe to travel.

Pit, Hidden

Mechanical trap

This pit has a cover constructed from material identical to the floor around it.

Trigger. The trap is triggered when a creature steps on the cover.

Effect. When triggered, the cover swings open like a trapdoor, causing the intruder to spill into the pit below. The pit is usually 10 or 20 feet deep but can be deeper.

Countermeasures. A successful DC 15 Wisdom (Perception) check discerns an absence of foot traffic over the section of floor that forms the pit’s cover. A successful DC 15 Intelligence (Investigation) check is necessary to confirm that the trapped section of floor is actually the cover of a pit.

Once the pit trap is detected, an iron spike or similar object can be wedged between the pit’s cover and the surrounding floor in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

Pit, Locking

Mechanical trap

This pit trap is identical to a hidden pit trap, with one key exception: the trap door that covers the pit is spring-loaded. After a creature falls into the pit, the cover snaps shut to trap its victim inside.

Countermeasures. A successful DC 20 Strength check is necessary to pry the cover open. The cover can also be smashed open (determine the cover’s statistics using the guidelines in chapter 8). A character in the pit can also attempt to disable the spring mechanism from the inside with a DC 15 Dexterity check using thieves’ tools, provided that the mechanism can be reached and the character can see. In some cases, a mechanism (usually hidden behind a secret door nearby) opens the pit.

Pit, Spiked

Mechanical trap

This pit trap is a simple, hidden, or locking pit trap with sharpened wooden or iron spikes at the bottom.

Effect. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes, in addition to any falling damage. Even nastier versions have poison smeared on the spikes. In that case, anyone taking piercing damage from the spikes must also make a DC 13 Constitution saving throw, taking an 22 (4d10) poison damage on a failed save, or half as much damage on a successful one.

Poison Darts

Mechanical trap

When a creature steps on a hidden pressure plate, poison-tipped darts shoot from spring-loaded or pressurized tubes cleverly embedded in the surrounding walls. An area might include multiple pressure plates, each one rigged to its own set of darts.

Trigger. The trap activates when more than 20 pounds of weight is placed on the pressure plate, releasing four darts.

Effect. Each dart makes a ranged attack with a +8 bonus against a random target within 10 feet of the pressure plate (vision is irrelevant to this attack roll). (If there are no targets in the area, the darts don’t hit anything.) A target that is hit takes 2 (1d4) piercing damage and must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one.

Countermeastures. The tiny holes in the walls are obscured by dust and cobwebs, or cleverly hidden amid bas-reliefs, murals, or frescoes that adorn the walls. The DC to spot them is 15. With a successful DC 15 Intelligence (Investigation) check, a character can deduce the presence of the pressure plate from variations in the mortar and stone used to create it, compared to the surrounding floor. Wedging an iron spike or other object under the pressure plate prevents the trap from activating. Stuffing the holes with cloth or wax prevents the darts contained within from launching.

Poison Needle

Mechanical trap

Trigger. A poisoned needle is hidden within a treasure chest’s lock, or in something else that a creature might open. Opening the chest without the proper key causes the needle to spring out, delivering a dose of poison.

Effect. When the trap is triggered, the needle extends 3 inches straight out from the lock. A creature within range takes 1 piercing damage and 11 (2d10) poison damage, and must succeed on a DC 15 Constitution saving throw or be poisoned for 1 hour.

Countermeastures. A successful DC 20 Intelligence (Investigation) check allows a character to deduce the trap’s presence from alterations made to the lock to accommodate the needle. A successful DC 15 Dexterity check using thieves’ tools disarms the trap, removing the needle from the lock. Unsuccessfully attempting to pick the lock triggers the trap.

Poison Needle, Paralyzing

Mechanical trap

A tiny, poisoned needle hidden in a lock is a good way to discourage thieves from plundering a hoard. Such a trap is usually put in a chest or in the door to a treasure chamber.

Trigger. Anyone attempting to pick or open the lock triggers the trap.

Effect. The triggering creature must make a DC 20 Constitution saving throw. On a failed save, the creature takes 14 (4d6) poison damage and is poisoned for 10 minutes. While poisoned in this way, the creature is paralyzed. On a successful save, the creature takes half as much damage and isn’t poisoned.

Countermeasures. A successful DC 20 Wisdom (Perception) check reveals the needle, but only if a character inspects the lock. A successful DC 20 Dexterity check using thieves’ tools disables the needle, and a check with a total of 10 or lower triggers the trap.

Scything Blade

Mechanical trap

This trap uses moving blades that sweep down through a chamber, threatening anyone nearby. Typically, a scything blade trap is activated by manipulating a lever or some other simple device. Kobolds especially like this kind of trap, since it can take down bigger creatures.

Trigger. When the lever is pulled, the trap activates.

Effect. Each Medium or larger creature in a 5-foot-wide, 20-foot-long area must make a DC 15 Dexterity saving throw, taking 14 (4d6) slashing damage on a failed save, or half as much damage on a successful one.

Countermeasures. The lever isn’t hidden. A successful DC 15 Wisdom (Perception) check involving the surfaces in the trap’s area of effect reveals scrape marks and bloodstains on the walls and floor. A successful DC 15 Dexterity check using thieves’ tools disables the lever.

Complex

Path of Blades

Complex trap

Hidden within a buried pyramid that marks the location of the Lost City of Cynidicea is the tomb of King Alexander and Queen Zenobia. The entrance to their tomb is a long hallway riddled with traps, accessible only by cunningly hidden secret doors. The hallway is 20 feet wide and 160 feet long. It is mostly clear. After 80 feet, the floor is broken and cracked, becoming difficult terrain until the 130-foot mark.

Trigger. This trap activates as soon as a non-undead creature enters the hallway, and it remains active while any non-undead creature is within the hall.

Initiative. The trap acts on initiative count 20 and initiative count 10.

Active Elements. The Path of Blades includes a set of whirling blades along the first 80 feet of the trap, crushing pillars that slam down from the ceiling to the floor before rising back up to the ceiling in the next 50 feet, and a rune of fear in its final 30 feet.

  • Whirling Blades (Initiative 20). The blades attack each creature in the first 80 feet of the hallway, with a +5 bonus to the attack roll and dealing 11 (2d10) slashing damage on a hit.

  • Crushing Pillars (Initiative 10). Each creature in the 50-foot-long area beyond the first 80 feet of the hallway must make a DC 15 Dexterity saving throw. On a failed save, a creature takes 11 (2d10) bludgeoning damage and is knocked prone. On a successful save, the creature takes half as much damage and isn’t knocked prone.

  • Rune of Fear (Initiative 10). Each creature in the 30-foot-long area beyond the Crushing Pillars must make a DC 15 Wisdom saving throw. On a failed saving throw, the creature becomes frightened by the rune, and it must immediately use its reaction to move its speed in the direction of the pillars. The frightened creature can’t move closer to the far end of the hallway until it uses its action to make a DC 15 Wisdom saving throw, which ends the frightened condition on itself on a success.

Dynamic Elements. The blades and the rune become more dangerous the longer the trap remains active.

  • Blades Accelerate. The blades move with increasing speed, slowing only when they hit a target. Each time the blades miss with an attack, their next attack becomes harder to avoid. After each miss, the blades’ attack bonus increases by 2, and their damage increases by 3 (1d6). These benefits apply until the blades hit a target, after which the values return to normal.

  • Rune’s Defense. Tampering with the Rune of Fear increases the trap’s power. Each successful check on an attempt to disable the rune increases the damage of the blades and the crushing pillars by 5 (1d10) and increases the rune’s saving throw DC by 1.

Constant Elements. The Whirling Blades and the Rune of Fear affect each creature that ends its turn in an area affected by these elements.

  • Whirling Blades. Any creature that ends its turn in the blades’ area is targeted by an attack: +5 attack bonus; 5 (1d10) slashing damage on a hit.

  • Rune of Fear. Any creature that ends its turn within 30 feet of the far end of the corridor must make a saving throw against the Rune of Fear effect.

Countermeasures. Each of the trap’s active elements can be thwarted by particular countermeasures.

  • Whirling Blades. Characters can smash the blades, damage their components, or discern how to avoid them. The blades are disabled if their attack bonus is reduced to −8. Ways to reduce it are described below.

    • Intelligence (Investigation), DC 15. As an action, a creature that can see the blades can attempt an Intelligence (Investigation) check. A successful check means that the character has learned how to anticipate the blades’ movement, imposing disadvantage on the blades’ attacks against the creature while it isn’t incapacitated.

    • Attack. A creature in the area can ready an attack to strike at one of the blades as it goes by. The blade gains advantage on its attack against the creature. The creature then attacks. Each blade has AC 15 and 15 hit points. Destroying a blade reduces the Whirling Blades attack bonus by 2.

    • Dexterity (Thieves’ Tools), DC 15. Creatures can use thieves’ tools in the area attacked by the blades to foil their mechanism. A successful check reduces the Whirling Blades attack bonus by 2.

  • Crushing Pillars. The pillars are not susceptible to countermeasures.

  • Rune of Fear. The rune can be disabled with three successful DC 15 Intelligence (Arcana) checks. Each check requires an action. A creature must be at the end of the hallway to attempt the check, and only one creature can work on this task at once. Once a creature attempts a check for this purpose, no other character can do so until the end of that creature’s next turn. Alternatively, the rune can be disabled with three successful castings of dispel magic (DC 13) targeting the rune.

Poisoned Tempest

Mechanical trap

This fiendish trap was built to eliminate intruders who infiltrate a yuan-ti temple. The trap is a room, 60 feet on a side, with 5-foot-wide stone doors in the middle of each wall. In each corner of the room stands a 10-foot-tall statue of a great serpent, coiled and ready to strike. The eyes in each statue are rubies worth 200 gp apiece.

Trigger. This trap activates when a ruby is pried from one of the statues. Each statue’s mouth slides open, revealing a 1-foot-wide pipe that runs down its throat.

Initiative. The trap acts on initiative count 20 and 10.

Active Elements. The trap fills the room with poison and other deadly effects.

  • Locked Doors (Initiative 20). The four doors to this room slam shut and are locked in place by magic. This effect activates only once, the first time the trap is triggered.

  • Poison Gas (Initiative 20). Poison gas floods the room. Each creature inside must make a DC 20 Constitution saving throw, taking 33 (6d10) poison damage on a failed save, or half as much damage on a successful one.

  • Tempest (Initiative 10). Air and gas boils from the trap. Roll a d6, and consult the following table.

Tempest Effects
d6 Effect
1 Hallucinatory gas scrambles the mind and senses. All Intelligence and Wisdom checks made in the room have disadvantage until the Tempest element activates again.
2 Explosive gas fills the area. If anyone holds an open flame, it causes an explosion. All creatures in the area must make a DC 20 Dexterity saving throw, taking 22 (4d10) fire damage on a failed save, or half as much damage on a successful one. The flame is then extinguished.
3 Weakening gas fills the room. All Strength and Dexterity checks made in the room have disadvantage until the Tempest element activates again.
4 Buffeting winds force each creature in the room to succeed on a DC 20 Strength saving throw or be knocked prone.
5 Smoke fills the room. Visibility is reduced to 1 foot until the next time the Tempest element activates.
6 Poison floods the room, forcing creatures to make saving throws as for the Poison Gas element.

Dynamic Element. The longer the poison gas remains in the room, the more lethal it becomes.

  • Increased Potency. The damage from the Poison Gas element increases by 11 (2d10) each round after it activates, to a maximum of 55 (10d10).

Countermeasures. There are a few ways that the trap can be overcome.

  • Open the Doors. Opening the doors is the quickest way to circumvent the trap, but they are warded with magic. To open the doors, a character must first succeed on a DC 20 Wisdom (Perception) check to find the locking mechanism. A successful DC 20 Intelligence (Arcana) check is then required to disable the sphere of force that surrounds the lock (dispel magic is ineffective against it). Success on a DC 20 Dexterity check using thieves’ tools picks the lock. Finally, a successful DC 20 Strength (Athletics) check is needed to push the door open. Each check requires an action.

  • Disable the Statues. A statue can be disabled by blocking the flow of gas from its mouth. Heavily damaging a statue is a bad idea, for doing so leaves the gas vents open. Reducing a statue to 0 hit points (AC 17; 20 hp; resistance to fire, piercing, and slashing damage; immune to poison and psychic damage) or making a successful DC 20 Strength check to break it cracks the statue and increases the Poison Gas damage by 5 (1d10). A successful DC 20 Dexterity check using thieves’ tools, or a successful DC 15 Strength check made to block up the statue with a cloak or similar object, decreases the poison damage by 5 (1d10). Once a character succeeds on the check, someone must remain next to the statue to keep it blocked up. When all four statues are blocked in this manner, the trap deactivates.

Rolling Sphere

Mechanical trap

Trigger. When 20 or more pounds of pressure are placed on this trap’s pressure plate, a hidden trapdoor in the ceiling opens, releasing a 10-foot-diameter rolling sphere of solid stone.

Initiative. Activation of the sphere requires all creatures present to roll initiative. The sphere rolls initiative with a +8 bonus. On its turn, it moves 60 feet in a straight line. The sphere can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain. Whenever the sphere enters a creature’s space or a creature enters its space while it’s rolling, that creature must succeed on a DC 15 Dexterity saving throw or take 55 (10d10) bludgeoning damage and be knocked prone.

The sphere stops when it hits a wall or similar barrier. It can’t go around corners, but smart dungeon builders incorporate gentle, curving turns into nearby passages that allow the sphere to keep moving.

Countermeasures. With a successful DC 15 Wisdom (Perception) check, a character can spot the trapdoor and pressure plate. A search of the floor accompanied by a successful DC 15 Intelligence (Investigation) check reveals variations in the mortar and stone that betray the pressure plate’s presence. The same check made while inspecting the ceiling notes variations in the stonework that reveal the trapdoor. Wedging an iron spike or other object under the pressure plate prevents the trap from activating.

  • Strength Check, DC 20. As an action, a creature within 5 feet of the sphere can attempt to slow it down with a Strength check. On a successful check, the sphere’s speed is reduced by 15 feet. If the sphere’s speed drops to 0, it stops moving and is no longer a threat.

Magical Traps

Simple

Fiery Blast

Magic trap

The temple of Pyremius, a god of fire, is threatened by thieves who seek to steal the fire opals displayed there by the priests in tribute to their god. A mosaic on the floor of the entryway to the inner sanctum delivers a fiery rebuke to intruders.

Trigger. Anyone who steps on the mosaic causes fire to erupt from it. Those who openly wear holy symbols of Pyremius don’t trigger this trap.

Effect. A 15-foot cube of fire erupts, covering the pressure plate and the area around it. Each creature in the area must make a DC 15 Dexterity saving throw, taking 24 (7d6) fire damage on a failed save, or half as much damage on a successful one.

Countermeasures. A successful DC 15 Wisdom (Perception) check reveals the presence of ash and faint burn marks in the area affected by this trap. A successful DC 15 Intelligence (Religion) check enables a creature to destroy the trap by defacing a key rune on the perimeter of the mosaic that is within reach; failing this check causes the trap to activate. A successful dispel magic (DC 15) cast on the runes destroys the trap.

Fire-Breathing Statue

Magic trap

This trap is activated when an intruder steps on a hidden pressure plate, releasing a magical gout of flame from a nearby statue. The statue can be of anything, including a dragon or a wizard casting a spell.

Trigger. The trap activates when more than 20 pounds of weight is placed on the pressure plate.

Effect. When the trap activates, the statue releases a 30-foot cone of fire. Each creature in the fire must make a DC 13 Dexterity saving throw, taking 22 (4d10) fire damage on a failed save, or half as much damage on a successful one.

Countermeasures. The DC is 15 to spot the pressure plate, as well as faint scorch marks on the floor and walls. A spell or other effect that can sense the presence of magic, such as detect magic, reveals an aura of evocation magic around the statue.

Wedging an iron spike or other object under the pressure plate prevents the trap from activating. A successful dispel magic (DC 13) cast on the statue destroys the trap.

Sleep of Ages

Magic trap

When a sleep of ages trap activates, a pressure plate unleashes a spell that threatens to send intruders into a deep slumber. The dungeon’s guardians can then more easily dispose of the sleepers.

Trigger. Stepping on the pressure plate triggers this trap.

Effect. When activated, this trap casts a sleep spell centered on the pressure plate, using a 9th-level spell slot.

Countermeasures. A successful DC 20 Wisdom (Perception) check reveals the pressure plate. A successful DC 20 Intelligence (Arcana) check made within 5 feet of the pressure plate disables the trap, and a check with a total of 10 or lower triggers it. A successful dispel magic (DC 19) cast on the pressure plate destroys the trap.

Sphere of Annihilation

Magic trap

Magical, impenetrable darkness fills the gaping mouth of a stone face carved into a wall. The mouth is 2 feet in diameter and roughly circular. No sound issues from it, no light can illuminate the inside of it, and any matter that enters it is instantly obliterated.

Countermeasures. A successful DC 20 Intelligence (Arcana) check reveals that the mouth contains a sphere of annihilation that can’t be controlled or moved. It is otherwise identical to a normal sphere of annihilation, as described in chapter 7, "Treasure."

Variation. Some versions of the trap include an enchantment placed on the stone face, such that specified creatures feel an overwhelming urge to approach it and crawl inside its mouth. This effect is otherwise like the sympathy aspect of the antipathy/sympathy spell. A successful dispel magic (DC 18) removes this enchantment.

Complex

Sphere of Crushing Doom

Magical trap

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.

Initiative. The trap acts on initiative count 10 (but see the dynamic element below).

Active Element. Although the trap is complex in nature, it has a single active element. That’s all it needs.

  • Sphere of Crushing Doom (Initiative 10). 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 (4d10) bludgeoning damage and is knocked prone. On a successful save, a creature takes half as much damage and isn’t knocked prone. Objects that block the sphere, such as a conjured wall, take maximum damage from the impact.

Dynamic Element. The longer it rolls, the more lethal the sphere becomes.

  • Speed Kills. After its turn, the sphere gains speed, represented by its damage increasing by 11 (2d10). While its damage is 55 (10d10) or greater, it acts on initiative count 20 and 10.

Countermeasures. The trap can be neutralized either by stopping the sphere or preventing it from teleporting.

  • Stop the Sphere. 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.

  • Disrupt the Portals. Either portal can be neutralized with three successful DC 20 Intelligence (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 (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 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.