Constriction

Version 0.28: 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 makes it much easier to defeat batty enemies like unseen horrors, and prevents monsters from fleeing. Only certain species and monsters are capable of doing this (see list below).

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

Playable species

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

Initiating 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 that has free tentacles. 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. The following monsters are immune: jellies, monsters, and insubstantial monsters.
• 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.

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 2d(Strength/5), which means that a character with 20 points of strength will do twice as much damage as a character with only 10. 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%.
• 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.
• 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 quick blade at minimum delay (3 auts), the previous amount will be multiplied by 3/10 (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
• Any source of blinking can get you free. It counts as two escape attempts.
  • Barachim can hop away
• Teleportation will always get you free after a delay.
  • While Formicids can't blink or teleport, shafting themselves will work in a pinch
• Casting Dragon Form or drinking a potion of lignification will greatly increase your size, making constriction more difficult (only tentacled monstrosities are large enough to constrict those forms)
• Zin's Sanctuary ability breaks constriction

History

• Since 0.18, to_hit only depends on Dexterity.