Constriction

Version 0.31: This article may not be up to date for the latest stable release of Crawl.

Constriction is the act of grabbing a target, preventing it from moving away, and crushing it to death over several turns. This lowers the evasion of the target, and prevents them from moving or blinking away.

List of constrictors

Monsters

• N Naga
• N Naga mage
• N Naga sharpshooter
• N Naga ritualist
• N Naga warrior
• N Nagaraja
• w Snaplasher vine
• S Ball python
• S Anaconda
• X Tentacled monstrosity
• w Starspawn tentacle
• x Octopode
• N Vashnia
• Grasping Roots
  • g Jorgrun
  • f Shambling mangrove

Playable species

• Octopode
• Naga - gains the ability at experience level 13.

Forms

• Serpent talisman

Other Constriction Effects

• Borgnjor's Vile Clutch
• Wand of roots

Initiating Constriction

Melee Constriction

Constriction can occur whenever a constriction-capable character or monster makes a melee attack (not necessarily Unarmed Combat). All the following conditions apply:

• The attacker is not constricting another creature, unless the attacker is an Octopode. Octopodes are capable of maintaining up to eight at once (it doesn't matter if you wield weapons or shields).
• The defender is not constricted or engulfed by another creature.
• The attacker must be able to see the victim.
• The attacker is not confused.
• The size of the attacker is greater than or equal to the size of the defender.
• The defender is not immune to constriction attacks (see below).
• The defender must be next to the attacker (weapons of reaching don't allow you to constrict non-adjacent targets).

If all the previous requisites are met, the game rolls the to_hit of the attacker and the evasion/SH of the defender. For the player this is the standard auxiliary attack to_hit. Its calculated as follows:

to_hit = 13 + DEX*0.75 + Fighting*0.3 + Slaying bonus + Other bonuses

For the monsters, it is basically:

to_hit = 18 + HD*1.5 + Other bonuses (replace 1.5 with 2.5 if the monster is a fighter i.e. naga warriors)

If the attack hits, the constriction starts.

Spell Constriction

For Borgnjor's Vile Clutch, wand of roots, or Grasping Roots, the following apply:

• The defender is not constricted or engulfed by another creature.
• The attacker must be able to see the victim.
• The defender is not immune to constriction attacks.
• The defender is not over deep water or lava.

These forms of constriction always hit.

Constriction Immunity

The following monsters are immune:

• jellies,
• spiny monsters,
• insubstantial monsters.

Player sources:

• insubstantial forms, like the Storm Form or wisp form,
• the Spiny mutation, which is available only to demonspawn,
• slick slippers unrand.

Maintaining Constriction

While the target is constricted, it will take an increasing amount of damage each turn, will be unable to move in any direction, and will suffer an evasion penalty (-3 EV for the player; for monsters EV is divided by 2 + body size). Attempting to move away will constitute an escape attempt, using all of the above variables along with the number of escape attempts thus far (successive attempts have better success rates) to determine whether or not the escape succeeds.

Damage Calculations

The amount of damage inflicted every 10 auts is:

 (Base damage) * (1 + log2(1 + Duration/5)) * (0.33 + 0.67 * (XL/27))

• Base damage: For players constricting in melee, this is equal to 2d(Strength/5). A character with 20 strength does twice the damage as a character with 10. When using Borgnjor's Vile Clutch or a wand of roots, it depends of the power of the cast. For monsters, it is the base damage of that particular attack.
• Duration modifier: The second factor means that the more time you have been constricting a monster the more damage you do. The damage is increased by approximately 20% each turn, so after 5 turns you will do twice as much damage as you did in the first turn. After the fifth turn the rate is a bit lower than 20%. Due to a bug, this modifier is not applied to players.
• Experience level modifier: The third factor means that your damage increases linearly with your experience level. A level 27 character will do thrice as much damage as one at level 1.

This damage is then modified as follows:

• AC reduction: Unlike most melee attacks, constriction is not reduced by a random number between 0 and AC; the damage reduction is a random number between 0 and 1 + AC/2. This means that constriction bypasses half of the AC.
• Time scale: The previous formula calculates how much damage you do every 10 auts. That amount needs to be scaled depending on how many auts you have spent in this turn. For example: if you are attacking with a dagger at minimum delay (5 aut), the previous amount will be multiplied by 5/10 (after AC reduction).

Escaping Constriction

Along with simply succeeding at an escape attempt, there are a number of other methods for breaking free:

• Killing the constrictor
• If the constrictor moves from its current tile, constriction ends (even if the destination is still adjacent to the constricted target)
  • The dispersal and distortion brands can force the constrictor to blink away (or be banished to the Abyss)
  • Casting Teleport Other, Dispersal or Disjunction has a similar effect
  • Forcing the constrictor back with Iskenderun's Mystic Blast may also work but may not be as effective against larger monsters
  • Casting Polar Vortex will force the enemy away from you much more aggressively
• Disabling the constrictor with confusion, paralysis, petrification, fear, or unconsciousness immediately breaks constriction
  • Charming or polymorphing the constrictor also breaks constriction (and likely prevents them from making future attempts)
  • Elyvilon's healing abilities may allow you to pacify the constrictor
• Becoming immune to constriction will immediately end the status.
  • Storm Form is immune to constriction.
  • Dragon Form is giant size, so it can only be constricted by tentacled monstrosities.
• Any source of blinking can get you free. It has improved odds as if you had already made an extra attempt.
  • Barachim can hop away, while Dithmenos gives Shadow Step. Both also have improved escape odds, like with blink.
• Teleportation will always let you escape constriction
• Formicid's shaft ability will always escape constriction
• Zin's Sanctuary ability breaks constriction
• Ru's Draw Out Power and Power Leap will always escape construction

History

• In 0.32, constriction will be reworked:
  • The duration modifier to damage will be removed.
  • Escape chance will be simplified for players. The odds will be 40/75/100% for 1/2/3 attempts. Blinking and related effects will always escape constriction.
  • Escape chance for monsters will be modified to include HD in the formula. The new formula is intended to make the wand of roots stronger in the early game while requiring more investment in Evocations in the late game.
  • Constriction will apply -10 EV to both players and monsters. This replaces the previous EV penalty.
  • Constriction damage and duration will be rebalanced for most sources:
    • Monster melee constriction will be randomized and higher, while having only a 66% chance to apply.
    • Grasping Roots will have a higher minimum and lower maximum duration. Its damage will also be reduced.
    • Player melee constriction will no longer care about Str.
    • All player sources will deal more damage.
• Since 0.18, to-hit only depends on Dexterity.
• Prior to 0.12, the duration modifier to damage was applied to players.