Difference between revisions of "Trap"

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'''Traps''' (represented by '''[[^]]''') are [[Dungeon features]] that harm the player or [[monster]]s who step on them. There are two types of traps: physical traps which are always revealed to the player, and exploration-triggered traps which are triggered by the player randomly during exploration. Most traps are magical in nature, but some vaults may also place mechanical ones.
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'''Traps''' (represented by '''[[^]]''') are [[Dungeon features]] that harm the player or [[monster]]s who step on them. There are two types of traps: physical traps, which are always revealed to the player, and [[#Malevolent Force|malevolent force]], which is triggered by the player randomly, on exploration. Most traps are magical in nature.
  
 
==Physical traps==
 
==Physical traps==
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There are six types of physical trap that generate randomly throughout the [[Dungeon]] and its branches:
 
There are six types of physical trap that generate randomly throughout the [[Dungeon]] and its branches:
* [[File:Temporary teleport trap.png]] '''[[Teleport trap]]s''', which teleport anything that steps on the trap while in line of sight of the player to a different location on the current level. Destroyed when triggered.
+
*[[File:Temporary teleport trap.png]] '''[[Teleport trap]]s''', which teleport anything that steps on the trap while in line of sight of the player to a different location on the current level. Destroyed when triggered.
* [[File:Alarm_trap.png]] '''[[Alarm trap]]s''', which make an extremely loud noise and apply [[Sentinel's Mark]] to the player when the player or any monster steps on the trap. Destroyed when triggered.
+
*[[File:Alarm_trap.png]] '''[[Alarm trap]]s''', which make an extremely loud noise and apply [[Sentinel's Mark]] to the player when the player or any monster steps on the trap. Destroyed when triggered.
* [[File:Shaft.png]] '''[[Shaft]]s''', which will cause monsters to fall 1-3 floors to a lower floor in the current branch when a monster steps on the shaft and fails a chance based on their intelligence and hit dice. Players can step on shafts safely, and pressing '''>''' will cause the player to fall through the shaft if they wish. Destroyed when triggered.
+
*[[File:Shaft.png]] '''[[Shaft]]s''', which will cause monsters to fall 1-3 floors to a lower floor in the current branch when a monster steps on the shaft and fails a chance based on their intelligence and hit dice. Players can step on shafts safely, and pressing '''>''' will cause the player to fall through the shaft if they wish. Destroyed when triggered.
* [[File:Dispersal_trap.png]] '''[[Dispersal trap]]s''', which blink the player and all monsters in line of sight of the trap when the player or a monster steps on the trap. These traps are permanent.
+
*[[File:Dispersal_trap.png]] '''[[Dispersal trap]]s''', which blink the player and all monsters in line of sight of the trap when the player or a monster steps on the trap. These traps are permanent.
* [[File:Zot_trap.png]] '''[[Zot trap]]s''', which cause random harmful effects to the player, possibly including teleporting them, creating dangerous summoned or durably summoned monsters, causing an explosion dealing damage to the player, or invoking dangerous levels of [[magical contamination]], when the player or any monster steps on the trap while in line of sight of the player. When monsters step on the trap, there is only a chance for the player to be affected—this is indicated by the message "The power of Zot is invoked against you!". These traps are permanent.
+
*[[File:Zot_trap.png]] '''[[Zot trap]]s''', which cause random harmful effects to the player, possibly including teleporting them, creating dangerous summoned or durably summoned monsters, causing an explosion dealing damage to the player, or invoking dangerous levels of [[magical contamination]], when the player or any monster steps on the trap while in line of sight of the player. When monsters step on the trap, there is only a chance for the player to be affected—this is indicated by the message "The power of Zot is invoked against you!". These traps are permanent.
* [[File:Web.png]] '''Webs''', found most commonly in the [[Spider's Nest]], can cause the player and non-[[List of spiders|spider]] monsters to become trapped and be given the Held status, halving their [[evasion]] and preventing melee and ranged combat. These traps are permanent, with the exception of those created by [[jumping spider]]s, which are temporary and destroyed when the player breaks or blinks out of them.
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*[[File:Web.png]] '''[[Web]]s''', found most commonly in the [[Spider's Nest]], can cause the player and non-[[List of arachnids|spider]] monsters to become trapped and be given the Held status, halving their [[evasion]] and preventing melee and ranged combat. Webs on the floor are permanent, while those created by [[Ensnare]] or [[jumping spider]]s are destroyed when the player breaks or blinks out of them.
  
 
There are three more types of physical trap that can only be generated by [[vault]]s, most notably being seen in the [[hall of Zot]] on [[Zot:5]] and the [[Tomb]]:
 
There are three more types of physical trap that can only be generated by [[vault]]s, most notably being seen in the [[hall of Zot]] on [[Zot:5]] and the [[Tomb]]:
  
* [[File:Teleport_trap.png]] '''Permanent teleport traps''', which have the same effect as regular teleport traps but are not destroyed when triggered.
+
*[[File:Teleport_trap.png]] '''Permanent teleport traps''', which have the same effect as regular teleport traps but are not destroyed when triggered.
* [[File:Net_trap.png]] '''[[Net trap]]s''', which fire a [[throwing net]] at the player, with [[to-hit]] dependent on the absolute depth of the trap, when the player or any monster steps on the trap while in line of sight of the player. These traps are triggered 2/3 of the time when stepped on by the player, and are destroyed when triggered.
+
*[[File:Net_trap.png]] '''[[Net trap]]s''', which fire a [[throwing net]] at the player, with [[to-hit]] dependent on the absolute depth of the trap, when the player or any [[monster intelligence|intelligent]] monster steps on the trap while in line of sight of the player. These traps are triggered 1/3 of the time when stepped on by the monster. Not destroyed when triggered.
* [[File:Pressure_plate.png]] '''[[Pressure plate]]s''', which usually release monsters to surround the player when anything steps on the trap in line of sight of the player. The monsters released depend on the branch: in most branches, 8 [[redback]]s will be released. In the [[Snake Pit]], this is replaced by 8 [[black mamba]]s and [[mana viper]]s, and in the [[Realm of Zot]], this is replaced by a "klown kar"—3-8 [[Killer Klown]]s will be released. A few vaults have pressure plates that trigger different effects. These are always destroyed when triggered.
+
*[[File:Pressure_plate.png]] '''[[Pressure plate]]s''', which usually release monsters to surround the player when anything steps on the trap in line of sight of the player. The monsters released depend on the branch: in most branches, 8 [[redback]]s will be released. In the [[Snake Pit]], this is replaced by 8 [[black mamba]]s and [[mana viper]]s, and in the [[Realm of Zot]], this is replaced by a "klown kar"—3-8 [[Killer Klown]]s will be released. A few vaults have pressure plates that trigger different effects. These are always destroyed when triggered.
  
There are five more types of mechanical traps that can be found exclusively in the [[Ossuary]]. With the exception of blade traps, these traps all have a limited number of shots<ref>{{source ref|0.25.1|traps.cc|85}}</ref> and are destroyed once their shots run out. The player has a 1/4 chance to trigger them when stepping on them, with the exception of blade traps, which are triggered 2/3 of the time. All mechanical traps deal more damage to the player than to monsters<ref>{{source ref|0.25.1|traps.cc|852}}</ref>.
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==Malevolent Force==
 
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When exploring new tiles that haven't been seen before, there is a depth-based chance that the player will trigger one of three '''malevolent force''' effects:
* [[File:Arrow_trap.png]] '''[[Arrow trap]]s''': fire arrows, dealing 1-15 damage to the player, or 1-7 damage to monsters. They have 3-11 shots.
+
*'''Alarm trap effect''': the same as if the player stepped on an alarm trap; causes an extremely loud noise and [[Sentinel's Mark|marks]] the player. This effect cannot be triggered on D:1-3.
* [[File:Blade_trap.png]] '''[[Blade trap]]s''': swing a large blade, dealing 48-76 damage to the player, or 10-38 damage to monsters. They are never destroyed.
+
*'''Shaft effect''': the same as if the player voluntarily took a physical shaft; causes the player to fall 1-3 floors deeper in the branch with no immediate way to return to the higher floor. See '''[[Shaft#Exploration Shafts|Exploration Shafts]]''' for when they can and can not trigger.
* [[File:Bolt trap.png]] '''[[Bolt trap]]s''': fire bolts, dealing 1-40 damage to the player, or 1-18 damage to monsters. They have 3-11 shots.
+
*'''Teleport effect''': causes you to be teleported to a random location on the current floor that is next to monsters, like the [[teleportitis]] mutation. This effect will fail to trigger if the game cannot find any such locations on the current floor.
* [[File:Needle_trap.png]] '''[[Needle trap]]s''': fire poisoned [[needle]]s, which may poison the target. They have 3-11 shots.
 
* [[File:Spear_trap.png]] '''[[Spear trap]]s''': fire spears, dealing 1-26 damage to the player, or 1-10 damage to monsters. They have 2-7 shots.
 
 
 
==Exploration-triggered traps==
 
When exploring new tiles that haven't been seen before, there is a depth-based chance that the player will trigger an exploration trap. There are three types of exploration traps that can be triggered:
 
* '''Alarm trap effect''': the same as if the player stepped on an alarm trap; causes an extremely loud noise and [[Sentinel's Mark|marks]] the player. This effect cannot be triggered on D:1 or D:2.
 
* '''Shaft effect''': the same as if the player voluntarily took a physical shaft; causes the player to fall 1-3 floors deeper in the branch with no immediate way to return to the higher floor. This effect cannot be triggered while standing on stairs or some other dungeon features, in the [[Tomb]], [[Pandemonium]], on the last floor of any branch, or on the second-last floor of all branches except the [[Dungeon]], [[Lair]], [[Orc]] and [[Depths]], and you cannot be shafted from a higher floor into the last floor of any branch except the [[Dungeon]], [[Lair]], [[Orc]] or [[Depths]].
 
* '''Teleport effect''': causes you to be teleported to a random location on the current floor that is next to monsters, like the [[teleportitis]] mutation. This effect will fail to trigger if the game cannot find any such locations on the current floor.
 
  
 
Note that new tiles revealed immediately after a shaft or teleport effect won't trigger another trap effect, giving the player a bit of a break post-trap.
 
Note that new tiles revealed immediately after a shaft or teleport effect won't trigger another trap effect, giving the player a bit of a break post-trap.
  
Worshippers of [[Ashenzari]] are completely immune to these effects.
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Worshippers of [[Ashenzari]] with at least 4* of piety are completely immune to these effects.
  
 
===Chance to trigger===
 
===Chance to trigger===
The chance for each of the alarm trap, shaft and teleport traps to trigger when an exploration trap effect is rolled is 1/3 for each.
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When malevolent force is triggered, it randomly chooses a valid effect with an equal chance of each.
  
The chance for a given turn exploring new tiles is:
+
The chance for a given turn to trigger a malevolent force effect is:
  
 
  (number of floor tiles revealed on this turn / number of floor tiles on current level) * (1 + absdepth of current level/10) / 9
 
  (number of floor tiles revealed on this turn / number of floor tiles on current level) * (1 + absdepth of current level/10) / 9
  
The chance for one or more exploration traps to trigger on a given level is therefore simply <code>(1 + absdepth/10) / 9</code>.
+
The chance for one or more malevolent forces to trigger on a given level is therefore simply <code>(1 + absdepth/10) / 9</code>.
 
This leads to the following chances of the game attempting to trigger one or more exploration-triggered traps on any given level:
 
This leads to the following chances of the game attempting to trigger one or more exploration-triggered traps on any given level:
 
{| class="prettytable"
 
{| class="prettytable"
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| D:1-9 || 1/9
 
| D:1-9 || 1/9
 
|-
 
|-
| D:10-15 || 2/9
+
| D:10-15<br>Lair<br>Orcish Mines || 2/9
|-
 
| Lair || 2/9
 
|-
 
| Orcish Mines || 2/9
 
|-
 
| Elven Halls || 2/9
 
|-
 
| Swamp/Shoals/Snake Pit/Spider Nest || 2/9
 
|-
 
| Slime:1-2 || 2/9
 
|-
 
| Slime:3-5 || 3/9
 
|-
 
| Vaults || 3/9
 
|-
 
| Depths || 3/9
 
|-
 
| Crypt || 3/9
 
|-
 
| Tomb || 3/9
 
 
|-
 
|-
| Pandemonium || 3/9
+
| Elven Halls<br>Swamp / Shoals<br>Snake Pit / Spider Nest<br>Slime:1-2  || 2/9
 
|-
 
|-
| Hell || 3/9
+
| Slime:3-5<br>Vaults<br>Depths || 3/9
 
|-
 
|-
| Geh/Coc/Tar/Dis:1 || 3/9
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| Crypt<br>Tomb<br>Pandemonium<br>Vestible of Hell<br>Hell Branch:1 || 3/9
 
|-
 
|-
| Geh/Coc/Tar/Dis:2-7 || 4/9
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| Hell Branch:2-7 || 4/9
 
|-
 
|-
 
| Zot:1-2 || 3/9
 
| Zot:1-2 || 3/9
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In some situations, monsters already know the locations of traps:
 
In some situations, monsters already know the locations of traps:
*Monsters native to a [[dungeon branch]] (eg. [[orc]]s in the [[Orcish Mines]]) already know the locations of all traps in their branch, since they live there.
+
*Monsters native to a [[dungeon branch]] (e.g. [[orc]]s 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, since it's assumed that you would tell them about the traps.
 
*Monsters friendly to the player, and good neutrals, know the location of all traps, since it's assumed that you would tell them about the traps.
 
*Monsters with human [[intelligence]] or greater have a 1 in 3 chance of knowing about the existence of any single trap.
 
*Monsters with human [[intelligence]] or greater have a 1 in 3 chance of knowing about the existence of any single trap.
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==Obsolete Traps==
 
==Obsolete Traps==
 
Over the years, many traps have been removed from the game for various reasons.
 
Over the years, many traps have been removed from the game for various reasons.
* [[File:Shadow_trap.png]] '''[[Shadow trap]]s''' were added in [[0.16]] and removed in [[0.17]].
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*'''Mechanical traps''' were all removed in [[0.27]].
* [[File:Gas_trap.png]] ''' [[Gas trap]]s''' were removed in [[0.13]].
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**[[File:Arrow_trap.png]] '''[[Arrow trap]]s'''.
* [[File:Axe_trap.png]]''' [[Axe trap]]s''' were removed in [[0.11]].
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**[[File:Blade_trap.png]] '''[[Blade trap]]s'''.
 +
**[[File:Bolt trap.png]] '''[[Bolt trap]]s'''.
 +
**[[File:Dart_trap.png]] '''[[Dart trap]]s'''.
 +
**[[File:Spear_trap.png]] '''[[Spear trap]]s'''.
 +
**[[File:Needle_trap.png]] '''[[Needle trap]]s''' were replaced with dart traps in [[0.24]].
 +
**[[File:Axe_trap.png]]''' [[Axe trap]]s''' were removed in [[0.11]].
 +
*[[File:Shadow_trap.png]] '''[[Shadow trap]]s''' were added in [[0.16]] and removed in [[0.17]].
 +
*[[File:Gas_trap.png]] ''' [[Gas trap]]s''' were removed in [[0.13]].
  
 
==History==
 
==History==
*Prior to [[0.25]], monsters couldn't spawn on top of traps. As a result, [[Animate Dead]] had no effect on [[corpse]]s that were on tiles with [[web]]s.
+
*Prior to [[0.31]], malevolent force was known as sourceless malevolence.
*In [[0.24]], exploration trap effects will be made to only pick from eligible exploration effects.
+
*Prior to [[0.29]], exploration [[shaft]] traps in the Dungeon branch didn't try to drop you into a place without monsters.
*Dispersal traps were added in [[0.23]]. Prior to [[0.23]], exploration-triggered traps did not exist, and physical traps were not always revealed to the player—instead, the player had an XL-based chance to detect physical traps and so would sometimes stumble into these traps. Worshippers of [[Ashenzari]] had an increased chance to detect these traps. Alarm and net traps did not affect the player when monsters stepped on the trap, and the trap layout in the [[hall of Zot]] in [[Zot:5]] and the [[Tomb]] was very different.
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*Prior to [[0.28]], sourceless malevolence effects was known as exploration traps, and exploration shaft traps were not limited to once per branch.
*Prior to [[0.16]], flying players and monsters could avoid triggering traps. Shadow traps were added and trap disarming was removed in this version.
+
*Prior to [[0.25]], monsters couldn't spawn on top of traps. As a result, [[Animate Dead]] had no effect on [[corpse]]s that were on tiles with [[web]]s. Also, scrolls of [[magic mapping]] didn't reveal traps.
 +
*In [[0.24]], exploration trap effects were made to only pick from eligible exploration effects.
 +
*In [[0.23]], traps were reworked. Prior to this version:
 +
**Exploration traps did not exist. Instead, physical traps were often hidden from the player, with an XL-based chance to be detected. [[Ashenzari]] increased the trap detection chance.
 +
**[[Dispersal trap]]s were introduced.
 +
**Alarm and net traps did not affect the player if a monster stepped on them.
 +
**Monsters could trigger physical traps, even if they were outside of the player's [[line of sight]].
 +
**The trap layout in areas like [[hall of Zot]] in [[Zot:5]] and the [[Tomb]] were very different.
 +
*Prior to [[0.16]], flying players and monsters could avoid triggering traps. Shadow traps were added, and trap disarming was removed in this version.
 
*Prior to [[0.15]], mechanical traps dropped ammunition and all teleport traps were permanent.
 
*Prior to [[0.15]], mechanical traps dropped ammunition and all teleport traps were permanent.
 
*Prior to [[0.13]], mechanical traps were randomly placed throughout every branch. Trap detection was based on the [[Traps (skill)|Traps]] skill.
 
*Prior to [[0.13]], mechanical traps were randomly placed throughout every branch. Trap detection was based on the [[Traps (skill)|Traps]] skill.

Latest revision as of 17:40, 25 January 2024

Version 0.31: This article is up to date for the latest stable release of Dungeon Crawl Stone Soup.

Traps (represented by ^) are Dungeon features that harm the player or monsters who step on them. There are two types of traps: physical traps, which are always revealed to the player, and malevolent force, which is triggered by the player randomly, on exploration. Most traps are magical in nature.

Physical traps

Physical traps are always revealed to the player (but not necessarily to monsters). They can only be triggered by the player, or by monsters when they are in line of sight of the player. Flying creatures trigger traps in the same way as non-flying creatures.

There are six types of physical trap that generate randomly throughout the Dungeon and its branches:

  • Temporary teleport trap.png Teleport traps, which teleport anything that steps on the trap while in line of sight of the player to a different location on the current level. Destroyed when triggered.
  • Alarm trap.png Alarm traps, which make an extremely loud noise and apply Sentinel's Mark to the player when the player or any monster steps on the trap. Destroyed when triggered.
  • Shaft.png Shafts, which will cause monsters to fall 1-3 floors to a lower floor in the current branch when a monster steps on the shaft and fails a chance based on their intelligence and hit dice. Players can step on shafts safely, and pressing > will cause the player to fall through the shaft if they wish. Destroyed when triggered.
  • Dispersal trap.png Dispersal traps, which blink the player and all monsters in line of sight of the trap when the player or a monster steps on the trap. These traps are permanent.
  • Zot trap.png Zot traps, which cause random harmful effects to the player, possibly including teleporting them, creating dangerous summoned or durably summoned monsters, causing an explosion dealing damage to the player, or invoking dangerous levels of magical contamination, when the player or any monster steps on the trap while in line of sight of the player. When monsters step on the trap, there is only a chance for the player to be affected—this is indicated by the message "The power of Zot is invoked against you!". These traps are permanent.
  • Web.png Webs, found most commonly in the Spider's Nest, can cause the player and non-spider monsters to become trapped and be given the Held status, halving their evasion and preventing melee and ranged combat. Webs on the floor are permanent, while those created by Ensnare or jumping spiders are destroyed when the player breaks or blinks out of them.

There are three more types of physical trap that can only be generated by vaults, most notably being seen in the hall of Zot on Zot:5 and the Tomb:

  • Teleport trap.png Permanent teleport traps, which have the same effect as regular teleport traps but are not destroyed when triggered.
  • Net trap.png Net traps, which fire a throwing net at the player, with to-hit dependent on the absolute depth of the trap, when the player or any intelligent monster steps on the trap while in line of sight of the player. These traps are triggered 1/3 of the time when stepped on by the monster. Not destroyed when triggered.
  • Pressure plate.png Pressure plates, which usually release monsters to surround the player when anything steps on the trap in line of sight of the player. The monsters released depend on the branch: in most branches, 8 redbacks will be released. In the Snake Pit, this is replaced by 8 black mambas and mana vipers, and in the Realm of Zot, this is replaced by a "klown kar"—3-8 Killer Klowns will be released. A few vaults have pressure plates that trigger different effects. These are always destroyed when triggered.

Malevolent Force

When exploring new tiles that haven't been seen before, there is a depth-based chance that the player will trigger one of three malevolent force effects:

  • Alarm trap effect: the same as if the player stepped on an alarm trap; causes an extremely loud noise and marks the player. This effect cannot be triggered on D:1-3.
  • Shaft effect: the same as if the player voluntarily took a physical shaft; causes the player to fall 1-3 floors deeper in the branch with no immediate way to return to the higher floor. See Exploration Shafts for when they can and can not trigger.
  • Teleport effect: causes you to be teleported to a random location on the current floor that is next to monsters, like the teleportitis mutation. This effect will fail to trigger if the game cannot find any such locations on the current floor.

Note that new tiles revealed immediately after a shaft or teleport effect won't trigger another trap effect, giving the player a bit of a break post-trap.

Worshippers of Ashenzari with at least 4* of piety are completely immune to these effects.

Chance to trigger

When malevolent force is triggered, it randomly chooses a valid effect with an equal chance of each.

The chance for a given turn to trigger a malevolent force effect is:

(number of floor tiles revealed on this turn / number of floor tiles on current level) * (1 + absdepth of current level/10) / 9

The chance for one or more malevolent forces to trigger on a given level is therefore simply (1 + absdepth/10) / 9. This leads to the following chances of the game attempting to trigger one or more exploration-triggered traps on any given level:

Branch Chance per floor
D:1-9 1/9
D:10-15
Lair
Orcish Mines
2/9
Elven Halls
Swamp / Shoals
Snake Pit / Spider Nest
Slime:1-2
2/9
Slime:3-5
Vaults
Depths
3/9
Crypt
Tomb
Pandemonium
Vestible of Hell
Hell Branch:1
3/9
Hell Branch:2-7 4/9
Zot:1-2 3/9
Zot:3-5 4/9

The above chances are for the game to attempt to trap the player. Given that there are many situations when the shaft and teleport effects can fail, this does not accurately reflect the chance of actually being trapped on a given floor. Situations when a particular trap effect fails are not announced.


Obsolete Traps

Over the years, many traps have been removed from the game for various reasons.

History

  • Prior to 0.31, malevolent force was known as sourceless malevolence.
  • Prior to 0.29, exploration shaft traps in the Dungeon branch didn't try to drop you into a place without monsters.
  • Prior to 0.28, sourceless malevolence effects was known as exploration traps, and exploration shaft traps were not limited to once per branch.
  • Prior to 0.25, monsters couldn't spawn on top of traps. As a result, Animate Dead had no effect on corpses that were on tiles with webs. Also, scrolls of magic mapping didn't reveal traps.
  • In 0.24, exploration trap effects were made to only pick from eligible exploration effects.
  • In 0.23, traps were reworked. Prior to this version:
    • Exploration traps did not exist. Instead, physical traps were often hidden from the player, with an XL-based chance to be detected. Ashenzari increased the trap detection chance.
    • Dispersal traps were introduced.
    • Alarm and net traps did not affect the player if a monster stepped on them.
    • Monsters could trigger physical traps, even if they were outside of the player's line of sight.
    • The trap layout in areas like hall of Zot in Zot:5 and the Tomb were very different.
  • Prior to 0.16, flying players and monsters could avoid triggering traps. Shadow traps were added, and trap disarming was removed in this version.
  • Prior to 0.15, mechanical traps dropped ammunition and all teleport traps were permanent.
  • Prior to 0.13, mechanical traps were randomly placed throughout every branch. Trap detection was based on the Traps skill.
  • Prior to 0.12, Traps could be detected by searching (command s).
  • Prior to 0.11, trap damage scaled with the floor's depth.

References