DM’s Toolbox

This chapter provides advice on rules for adventure elements such as poison and traps.

Poison

Given their insidious and deadly nature, poisons are a favorite tool among assassins and evil creatures.

Poisons come in the following four types:

Contact. Contact poison can be smeared on an object and remains potent until it is touched or washed off. A creature that touches contact poison with exposed skin suffers its effects.

Ingested. A creature must swallow an entire dose of ingested poison to suffer its effects. The dose can be delivered in food or a liquid. You may decide that a partial dose has a reduced effect, such as allowing Advantage on the saving throw or dealing only half as much damage on a failed save.

Inhaled. Poisonous powders and gases take effect when inhaled. Blowing the powder or releasing the gas subjects creatures in a 5-foot Cube to its effect. The resulting cloud dissipates immediately afterward. Holding one’s breath is ineffective against inhaled poisons, as they affect nasal membranes, tear ducts, and other parts of the body.

Injury. Injury poison can be applied as a Bonus Action to a weapon, a piece of ammunition, or similar object. The poison remains potent until delivered through a wound or washed off. A creature that takes Piercing or Slashing damage from an object coated with the poison is exposed to its effects.

Sample Poisons

Example poisons are detailed here in alphabetical order. Each poison’s description includes the suggested price for a single dose of the poison, its type (contact, ingested, inhaled, or injury), and a description of the poison’s debilitating effects.

Assassin’s Blood (150 GP)

Ingested Poison

A creature subjected to Assassin’s Blood makes a DC 10 Constitution saving throw. On a failed save, the creature takes 6 (1d12) Poison damage and has the Poisoned condition for 24 hours. On a successful save, the creature takes half as much damage only.

Burnt Othur Fumes (500 GP)

Inhaled Poison

A creature subjected to Burnt Othur Fumes must succeed on a DC 13 Constitution saving throw or take 10 (3d6) Poison damage, and it must repeat the save at the start of each of its turns. On each successive failed save, the creature takes 3 (1d6) Poison damage. After three successful saves, the poison ends.

Carrion Crawler Mucus (200 GP)

Contact Poison

A creature subjected to Carrion Crawler Mucus must succeed on a DC 13 Constitution saving throw or have the Poisoned condition for 1 minute. The creature also has the Paralyzed condition while Poisoned in this way. The creature repeats the save at the end of each of its turns, ending the effect on itself on a success.

Essence of Ether (300 GP)

Inhaled Poison

A creature subjected to Essence of Ether must succeed on a DC 15 Constitution saving throw or have the Poisoned condition for 8 hours. The creature also has the Unconscious condition while Poisoned in this way. The creature wakes up if it takes damage or if another creature takes an action to shake it awake.

Lolth’s Sting (200 GP)

Injury Poison

A creature subjected to Lolth’s Sting must succeed on a DC 13 Constitution saving throw or have the Poisoned condition for 1 hour. If the creature fails the save by 5 or more, the creature also has the Unconscious condition while Poisoned in this way. The creature wakes up if it takes damage or if another creature takes an action to shake it awake.

Malice (250 GP)

Inhaled Poison

A creature subjected to Malice must succeed on a DC 15 Constitution saving throw or have the Poisoned condition for 1 hour. The creature also has the Blinded condition while Poisoned in this way.

Midnight Tears (1,500 GP)

Ingested Poison

A creature that ingests Midnight Tears suffers no effect until the stroke of midnight. Any effect that ends the Poisoned condition neutralizes this poison. If the poison hasn’t been neutralized before midnight, the creature makes a DC 17 Constitution saving throw, taking 31 (9d6) Poison damage on a failed save or half as much damage on a successful one.

Oil of Taggit (400 GP)

Contact Poison

A creature subjected to Oil of Taggit must succeed on a DC 13 Constitution saving throw or have the Poisoned condition for 24 hours. The creature also has the Unconscious condition while Poisoned in this way. It wakes up if it takes damage.

Pale Tincture (250 GP)

Ingested Poison

A creature subjected to Pale Tincture must succeed on a DC 16 Constitution saving throw or take 3 (1d6) Poison damage and have the Poisoned condition. The Poisoned creature repeats the save every 24 hours, taking 3 (1d6) Poison damage on a failed save. The damage the poison deals can’t be healed by any means while the creature remains Poisoned. After seven successful saves against the poison, the creature is no longer Poisoned.

Purple Worm Poison (2,000 GP)

Injury Poison

A creature subjected to Purple Worm Poison makes a DC 21 Constitution saving throw, taking 35 (10d6) Poison damage on a failed save or half as much damage on a successful one.

Serpent Venom (200 GP)

Injury Poison

A creature subjected to Serpent Venom must succeed on a DC 11 Constitution saving throw, taking 10 (3d6) Poison damage on a failed save or half as much damage on a successful one.

Torpor (600 GP)

Ingested Poison

A creature subjected to Torpor poison must succeed on a DC 15 Constitution saving throw or have the Poisoned condition for 4d6 hours. The creature’s Speed is halved while the creature is Poisoned in this way.

Truth Serum (150 GP)

Ingested Poison

A creature subjected to Truth Serum must succeed on a DC 11 Constitution saving throw or have the Poisoned condition for 1 hour. The Poisoned creature can’t knowingly communicate a lie.

Wyvern Poison (1,200 GP)

Injury Poison

A creature subjected to Wyvern Poison makes a DC 14 Constitution saving throw, taking 24 (7d6) Poison damage on a failed save or half as much damage on a successful one.

Traps

Traps should be used sparingly, lest they lose their charm. A hidden pit can be a fun surprise, but too many traps in an adventure can lead players to become overly cautious, which slows down the game.

The best traps are fleeting distractions that skilled characters can overcome in a short amount of time or deadly puzzles that require quick thinking and teamwork to overcome. Traps that are undetectable and inescapable are rarely fun.

Parts of a Trap

The description of a trap includes the following parts after the trap’s name:

Severity and Levels. A trap is designated as a nuisance or as deadly for characters of certain levels. A nuisance trap is unlikely to kill or seriously harm characters of the indicated levels, whereas a deadly trap can grievously damage characters of the indicated levels.

Trigger. Traps are often set to go off when a creature enters an area or touches an object. Examples of triggers include stepping on a pressure plate, crossing a trip wire, turning a doorknob, or using the wrong key in a lock.

Duration. Some traps have durations expressed in rounds, minutes, or hours. Others specify that their effects last until the trap is destroyed or dispelled. If a trap’s duration is instantaneous, its effect is resolved instantly.

Use caution when introducing a trap to characters of a level lower than the trap’s level range. A trap that is a nuisance at one level range could be deadly to characters of a lower level range.

Example Traps

Traps are presented in alphabetical order.

Collapsing Roof

Deadly Trap (Levels 1–4)

Trigger: A creature crosses a trip wire

Duration: Instantaneous

This trap uses a trip wire to collapse an unstable section of ceiling. The trip wire is 3 inches off the ground and stretches between two weak supports that topple when the trip wire is pulled.

The first creature that crosses the trip wire causes the supports to topple and the unstable section of ceiling to collapse. Each creature beneath the unstable section of ceiling must succeed on a DC 13 Dexterity saving throw, taking 11 (2d10) Bludgeoning damage on a failed save or half as much damage on a successful one. Rubble from the collapse turns the trapped area into Difficult Terrain.

Detect and Disarm. As a Search action, a creature can examine the trapped area and make a DC 11 Wisdom (Perception) check, detecting the trip wire and the unstable section of ceiling on a successful check. Once detected, the trip wire can be easily cut or avoided (no ability check required).

At Higher Levels. You can scale the trap for higher levels by increasing the damage and the save DC, as shown in the following table.

Levels Bludgeoning Damage Save DC
5–10 22 (4d10) 15
11–16 55 (10d10) 17
17–20 99 (18d10) 19

Falling Net

Nuisance Trap (Levels 1–4)

Trigger: A creature crosses a trip wire

Duration: Instantaneous

A falling net trap uses a trip wire to release a weighted, 10-foot-square Net suspended from the ceiling. The trip wire is 3 inches off the ground and stretches between two columns or trees.

The first creature that crosses the trip wire causes the Net to fall on it. The target must succeed on a DC 10 Dexterity saving throw or have the Restrained condition until it escapes. The target succeeds automatically if it’s Huge or larger. A creature can take an action to make a DC 10 Strength (Athletics) check, freeing itself or another creature within its reach from the Net on a successful check.

Detect and Disarm. As a Search action, a creature can examine the trapped area and make a DC 11 Wisdom (Perception) check, detecting the trip wire and the suspended Net on a successful check. Once detected, the trip wire can be easily cut or avoided (no ability check required).

Destroy the Net. Reducing the Net to 0 Hit Points frees any creature trapped in it (see the Player’s Handbook for the Net’s statistics).

Set the Trap. A creature that has Thieves’ Tools and all the trap’s components (including a Net) can try to set a falling net trap, doing so with a successful DC 13 Dexterity (Sleight of Hand) check. Each attempt to set this trap takes 10 minutes.

At Higher Levels. You can scale the trap for higher levels by increasing the weight of the Net, which increases the save DC and the DC of the Strength (Athletics) check as follows: DC 12 at levels 5–10, DC 14 at levels 11–16, or DC 16 at levels 17–20.

Fire-Casting Statue

Deadly Trap (Levels 1–4)

Trigger: A creature moves onto a pressure plate

Duration: Instantaneous

When a creature moves onto this trap’s pressure plate for the first time on a turn or starts its turn there, a nearby statue exhales a 15-foot Cone of magical flame. The statue can look like anything, such as a dragon or a wizard. Each creature in the Cone must succeed on a DC 15 Dexterity saving throw, taking 11 (2d10) Fire damage on a failed save or half as much damage on a successful one.

Detect and Disarm. A Detect Magic spell reveals an aura of Evocation magic around the statue. As a Search action, a creature within 5 feet of the statue can examine it and make a DC 10 Wisdom (Perception) check, detecting a tiny glyph on the statue on a successful check. Once the glyph is found, a character can take a Study action to examine it and make a DC 15 Intelligence (Arcana) check, ascertaining that the glyph means “fire” on a successful check. As an action, a character can use a sharp tool to deface the glyph, which disarms the trap.

As a Search action, a creature can examine the section of floor that forms the pressure plate and make a DC 15 Wisdom (Perception) check, detecting the pressure plate on a successful check. Wedging an Iron Spike or similar object under the pressure plate prevents the trap from triggering.

At Higher Levels. You can scale the trap for higher levels by increasing the damage and the area of effect, as shown in the following table.

Levels Fire Damage Area of Effect
5–10 22 (4d10) 30-foot Cone
11–16 55 (10d10) 60-foot Cone
17–20 99 (18d10) 120-foot Cone

Hidden Pit

Nuisance Trap (Levels 1–4)

Trigger: A creature moves onto the pit’s lid

Duration: Instantaneous

This 10-foot-deep pit has a hinged lid constructed from material identical to the surrounding floor. When a creature moves onto the lid, it swings open like a trapdoor, causing the creature to fall into the pit. The lid remains open thereafter.

A creature that falls into the pit takes 3 (1d6) Bludgeoning damage from the fall.

Detect and Disarm. As a Study action, a creature can examine the section of floor that forms the pit’s lid and make a DC 15 Intelligence (Investigation) check, detecting the pit on a successful check. Once the pit is detected, an Iron Spike or a similar object can be wedged between the pit’s lid and the surrounding floor to prevent the lid from opening, thereby making it safe to cross. The cover can also be held shut using Arcane Lock or similar magic.

Escape. A creature needs a Climb Speed, climbing gear, or magic such as Spider Climb to scale the pit’s smooth walls. (You can make the pit easier to escape by adding cracks in the walls big enough to serve as handholds and footholds.)

At Higher Levels. You can scale the trap for higher levels by increasing the pit’s depth and damage, as shown in the following table.

Levels Pit Depth Bludgeoning Damage
5–10 30 feet 10 (3d6)
11–16 60 feet 21 (6d6)
17–20 120 feet 42 (12d6)

Poisoned Darts

Deadly Trap (Levels 1–4)

Trigger: A creature moves onto a pressure plate

Duration: Instantaneous

When a creature moves onto this trap’s pressure plate for the first time on a turn, poisoned darts shoot from tubes embedded in the surrounding walls. The holes that house these tubes are obscured by dust and cobwebs, or skillfully hidden amid bas-reliefs, murals, or frescoes.

Each creature in the darts’ path must succeed on a DC 13 Dexterity saving throw or be struck by 1d3 darts, taking 3 (1d6) Poison damage per dart.

Detect and Disarm. As a Search action, a creature can examine the walls and make a DC 15 Wisdom (Perception) check, detecting the holes on a successful check. Plugging all the holes with wax, cloth, or detritus prevents the darts from firing.

As a Search action, a creature can examine the section of floor that forms the pressure plate and make a DC 15 Wisdom (Perception) check, detecting the pressure plate on a successful check. Wedging an Iron Spike or a similar object under the pressure plate prevents the trap from triggering.

At Higher Levels. You can scale the trap for higher levels by increasing each dart’s Poison damage as follows: 7 (2d6) at levels 5–10, 14 (4d6) at levels 11–16, or 24 (7d6) at levels 17–20.

Poisoned Needle

Nuisance Trap (Levels 1–4)

Trigger: A creature opens the trap’s lock improperly or fails to disarm the trap

Duration: Instantaneous

A poisoned needle is hidden in a lock. When a creature opens the lock with any object other than the proper key, the needle springs out and stabs the creature. The creature makes a DC 11 Constitution saving throw. On a failed save, the creature takes 5 (1d10) Poison damage and has the Poisoned condition for 1 hour. On a successful save, the creature takes half as much damage only.

Avoid. The trap doesn’t trigger if the lock is opened using a Knock spell or similar magic.

Detect and Disarm. As a Search action, a creature can examine the trapped lock and make a DC 15 Wisdom (Perception) check, detecting the needle on a successful check. Once the trap is detected, a character can take an action to try to disarm the trap, doing so with a successful DC 15 Dexterity (Sleight of Hand) check. On a failed check, the creature triggers the trap.

At Higher Levels. You can scale the trap for higher levels by increasing the damage and the save DC, as shown in the following table.

Levels Poison Damage Save DC
5–10 11 (2d10) 13
11–16 22 (4d10) 15
17–20 55 (10d10) 17

Rolling Stone

Deadly Trap (Levels 11–16) or Nuisance Trap (Levels 17–20)

Trigger: A creature moves onto a pressure plate

Duration: Until the stone stops rolling

When a creature moves onto a hidden pressure plate, a 5-foot-radius orb of solid stone is released from a secret compartment and begins to roll. The stone and all creatures nearby roll Initiative; the stone gets a +8 bonus on its Initiative roll.

On its turn, the stone moves 60 feet in one direction, changing course if redirected by an obstacle. The stone can move through creatures’ spaces, and creatures can move through the stone’s space, treating it as Difficult Terrain. Whenever the stone enters a creature’s space for the first time on a turn or a creature enters the stone’s space while the stone is rolling, that creature must succeed on a DC 15 Dexterity saving throw or take 55 (10d10) Bludgeoning damage and have the Prone condition.

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

Detect and Disarm. As a Study action, a creature can examine the section of floor that forms the pressure plate and make a DC 15 Intelligence (Investigation) check, deducing the pressure plate’s function on a successful check. Wedging an Iron Spike or a similar object under the pressure plate prevents the trap from triggering.

Destroy the Stone. The stone is a Large object that has AC 17, HP 100, a Damage Threshold of 10, and Immunity to Poison and Psychic damage.

Slow the Stone. As an action, a creature can try to slow down the stone with a DC 20 Strength (Athletics) check. If the check is successful, the distance the stone moves on its turn is reduced by 15 feet. If that distance drops to 0, it stops moving and is no longer a threat.

Spiked Pit

Deadly Trap (Levels 1–4)

Trigger: A creature moves onto the pit’s lid

Duration: Instantaneous

A 10-foot-deep pit has a hinged lid constructed from material identical to the surrounding floor. When a creature moves onto the lid, it swings open like a trapdoor, causing the creature to fall into the pit, which has sharpened wooden or metal spikes at the bottom. The lid remains open thereafter.

A creature that falls into the pit lands at the bottom and takes 3 (1d6) Bludgeoning damage from the fall plus 9 (2d8) Piercing damage from the spikes.

Detect and Disarm. As a Study action, a creature can examine the section of floor that forms the pit’s lid and make a DC 15 Intelligence (Investigation) check, detecting the pit on a successful check. Once the hidden pit is detected, an Iron Spike or a similar object can be wedged between the pit’s lid and the surrounding floor to prevent the lid from opening, thereby making it safe to cross. The cover can also be held shut using an Arcane Lock spell or similar magic.

Escape. A creature needs a Climb Speed, climbing gear, or magic such as a Spider Climb spell to scale the pit’s smooth walls. You can make the pit easier to escape by adding cracks in the walls big enough to serve as handholds and footholds.

At Higher Levels. You can scale the trap for higher levels by increasing the pit’s depth and damage, as shown in the following table.

Levels Pit Depth Damage
5–10 30 feet 10 (3d6) Bludgeoning plus 13 (3d8) Piercing
11–16 60 feet 21 (6d6) Bludgeoning plus 36 (8d8) Piercing
17–20 120 feet 42 (12d6) Bludgeoning plus 57 (13d8) Piercing