Trap

Version 0.13: This article may not be up to date for the latest stable release of Crawl.

Traps (represented by ^) are Dungeon features that harm characters or monsters who step on them. They do not appear on the map until detected, except in some vaults. Most traps are magical in nature, but some vaults may also place mechanical ones.

Strategy

Your chance to detect traps depends on your experience level and the distance to the trap, and can be increased by worshiping Ashenzari, and decreased by the Blurry Vision mutation.

You can attempt to disarm a mechanical trap by holding CTRL and pressing the key corresponding to the direction of the trap (to attempt to disarm a trap to the right of you, for example, hold CTRL and press →). There is a low chance of disarming the trap with low Traps skill, and failing to disarm it is likely to trigger the trap.

Flying allows you to move over mechanical traps without triggering them.

Traps that fire ammunition have a limited supply of ammo.

Once you have detected a trap, you can (with thoughtful maneuvering) use it to harm or block monsters who are pursuing you. More intelligent monsters are much more likely to avoid them, however.

Trap Mechanics

Mechanical traps do not always go off when stepped on. The odds of setting one off are:

• For traps the player knows about:
  • 2 in 3 chance for blade and net traps.
  • 1 in 4 chance for all other traps.
• For traps the player does not know about:
  • Blade and net traps always go off.
  • 4 in 5 chance for all other traps.

For monsters, the odds are different:

• For traps the monster knows about:
  • 1 in 2 chance for blade and net traps.
  • All other traps always go off.
• For traps the monster does not know about:
  • 4 in 5 chance for blade traps.
  • 2 in 3 chance for net traps.
  • All other traps always go off.

If a mechanical trap is triggered, there is still a chance for the trap's weapon to miss, depending on your evasion and dexterity. The Repel Missiles and Deflect Missiles spells reduce the chance of a projectile hitting (except for the net trap, which drops the net rather than firing it). If you fail to evade the projectile, but are wearing a shield, you may instead block the projectile.

Monsters & Traps

Different monsters react differently to traps. Most monsters with animalistic intelligence or above will avoid ones they know about, and refuse to cross a trap even if there is no other way to reach you. Mindless monsters like zombies will walk through traps regardless of how much damage it might cause them. Zot traps are special: if you're in sight when a hostile monster walks into one, you get zapped. ("[It] uses the power of Zot against you!")

Flying monsters can evade mechanical traps without triggering them, just like players.

In some situations, monsters already know the locations of traps:

• Monsters native to a dungeon branch (eg. orcs in the Orcish Mines) already know the locations of all traps in their branch, since they live there.
• Monsters friendly to the player, and good neutrals, know the location of all traps that you know about, since it's assumed that you would tell them about the traps.
• Monsters with high intelligence or greater have a 1 in 3 chance of knowing about the existence of any single trap.

Trap Types

Notes:

• Only teleport, shaft, alarm and Zot traps are placed randomly.
• Shaft traps won't be placed in corridors in the first 7 levels of the dungeon.
• All ammunition produced by traps is unbranded and unenchanted.
• The damage caused by mechanical traps is reduced by the player's AC.

Trap	Description	Amount of ammo	Base damage to player	Base damage to monsters	Trap type
Alarm trap	Makes a loud noise and afflicts you with the Sentinel's Mark status effect	N/A	None	None	Magical
Shaft	Opens a hole under the victim, sending them to a deeper dungeon level	N/A	None	None	Natural
Teleport trap	Teleports the victim to a random location on the level	N/A	None	None	Magical
Zot trap	Produces a powerful magical miscast effect	N/A	Varies by effect	Varies by effect; only affects friendly monsters	Magical
Arrow trap	Fires an arrow	3 - 11	1 - 15	1 - 7	Mechanical
Blade trap	Swings a huge swinging blade	N/A	48 - 76	10 - 38	Mechanical
Bolt trap	Fires a bolt	3 - 11	1 - 40	1 - 18	Mechanical
Dart trap	Fires a dart	3 - 11	1 - 6	1 - 4	Mechanical
Needle trap	Fires a poisoned needle	3 - 11	None, but may poison	None, but may poison	Mechanical
Net trap	Drops a throwing net	1	None	None	Mechanical
Pressure plate	Causes something to happen, usually bad.	N/A	None	None	Mechanical
Spear trap	Fires a spear	2 - 7	1 - 26	1 - 10	Mechanical
Web	Induces the held status for several turns	May break after each use	None	None	Mechanical

Note that the "pressure plate" trap is a "software trap"; rather than a fixed result, its effects are scripted in Lua, and might include stuff like dumping out a basket of spiders, or dropping a grating to block the path behind you.

History

Prior to 0.13 there were Gas traps and mechanical ones could be randomly placed. Prior to 0.12, Traps could be detected by searching (command s). Prior to 0.11, axe traps existed and would launch hand axes when triggered, much like spear traps.