Caustic Arrow

Caustic ArrowAttack, AoE, Duration, Chaos, Bow
Radius: 20
Mana Cost: (8 to 16)
Cast Time: 1.00 sec
Projectile Speed: 3260Requires Level 4Fires an arrow which deals additional chaos damage to enemies it hits, and creates a caustic cloud. Enemies in the cloud take chaos damage over time.Per 1% Quality:
0.5% increased Area of EffectBase duration is (2.8-4.8) seconds
Deals (5.3-765) Base Chaos Damage per second
Gain (30-49)% of your Physical Damage as Extra Chaos Damage
Modifiers to Projectile Damage apply to this Skill's Damage Over Time effect
+(0-4) to radiusPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket.Acquisition
Level: 5Purchase Costs

Normal

1x Scroll of Wisdom

Sell Price
1x Scroll Fragment

Borrowing a bit of toxic chemistry from the secretive Oriath Necromancers guild, a skilled archer infuses their arrowhead with a wicked venom. Once enchanted, the arrow will explode violently when it impacts a target, showering both foes and the surrounding area with a cloud of choking death. Anything living caught in the cloud will suffocate quickly, suffering heavy chaos damage until they move far away.

Description on the official Path of Exile website

Caustic Arrow is a bow attack that fires an arrow dealing chaos damage and exploding in a caustic cloud. Enemies standing within it receive a debuff that deals chaos damage over time. The caustic cloud does not poison and is therefore not affected by poison-related modifiers.

Skill functions and interactions

• Caustic Arrow will explode either at the targeted location or on the first monster or obstacle it hits.

• Multiple projectiles: additional projectiles added will cause additional caustic clouds, but debuffs from multiple clouds do not stack.

• Piercing: piercing Caustic Arrow projectiles will cause additional clouds each time they hit and will receive the chaos damage bonus any time they impact an enemy.

• Projectile damage: passive nodes and gems (such as Slower Projectiles SupportSlower Projectiles SupportSupport, Projectile
  Icon: J
  Mana Multiplier: 140%Requires Level 31Supports projectile skills.Per 1% Quality:
  Supported Skills deal 0.5% increased Projectile DamageSupported Skills have (30-49)% less Projectile Speed
  Supported Skills deal (20-29)% more Projectile DamageThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Active Skill Gem you wish to augment. Right click to remove from a socket.) that increase projectile damage will increase both the damage on hit and the area of effect damage.

• Concentrated Effect: Concentrated Effect SupportConcentrated Effect SupportSupport, AoE
  Icon: o
  Mana Multiplier: 140%Requires Level 18Supports any skill with an area of effect, regardless of whether that skill deals damage.Per 1% Quality:
  Supported Skills deal 0.5% increased Area DamageSupported Skills have 30% less Area of Effect
  Supported Skills deal (35-54)% more Area DamageThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Active Skill Gem you wish to augment. Right click to remove from a socket. decreases the size of the AoE and increase its damage. However, due to the nature of the skill and the wording of its modifiers, the damage increase will not appear on the tooltip.

• Point Blank: Point Blank does not affect the caustic cloud damage, it only affects projectile attack damage.

• Iron Grip: The strength bonus from the Iron Grip keystone passive does not affect the caustic cloud damage because the cloud is not considered an attack nor is it based on physical damage. The increased projectile damage portion of the Iron Grip SupportIron Grip SupportProjectile, Support
  Icon: iRequires Level 18Supports attack skills that fire projectiles, making the increase to physical melee damage from strength also increse their physical projectile damage.Per 1% Quality:
  Supported Skills deal 0.5% increased Projectile DamageStrength's damage bonus applies to Projectile Attacks made with Supported Skills
  Supported Skills deal (0-38)% increased Projectile DamageThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Active Skill Gem you wish to augment. Right click to remove from a socket. will increase the cloud damage, but the strength bonus the support gem shares with the keystone will not apply.

• Accuracy: The projectile attack is subject to accuracy and can miss. However, the explosion will create a caustic cloud and do damage regardless of whether the projectile attack hit or missed. Piercing Caustic Arrow will not create additional clouds if missed.

• Duration: modifiers to duration will affect the duration of the caustic cloud.

• Culling strike: The increased damage from Culling Strike SupportCulling Strike SupportSupport
  Icon: X
  Mana Multiplier: 110%Requires Level 18Supports any skill that hits enemies. If enemies are left below 10% of maximum life after being hit by these skills, they will be killed.Per 1% Quality:
  Supported Skills have 0.5% increased Attack Speed
  Supported Skills have 0.5% increased Cast SpeedKill Enemies that have 10% Life or lower when Hit by Supported Skills
  Supported Skills deal (0-38)% increased DamageThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Active Skill Gem you wish to augment. Right click to remove from a socket. applies to cloud damage, but the cloud does not kill enemies instantly when they have less than 10% life.

• Curses: Projectile WeaknessProjectile WeaknessCurse, Spell, AoE, Duration
  Radius: 22
  Mana Cost: (24 to 50)
  Cast Time: 0.50 secRequires Level 24Curses all targets in an area, making them easier to pierce and to knock back, and increasing the damage they take from projectiles.Per 1% Quality:
  Cursed enemies take 0.5% increased Damage from ProjectilesBase duration is (9-10.9) seconds
  Projectiles Pierce Cursed Enemies
  Hits on Cursed Enemies have an additional 25% chance to Knockback
  Cursed enemies take (25-44)% increased Damage from Projectiles
  +(0-10) to radiusPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. requires the target to be hit. The caustic cloud won't be affected by it. VulnerabilityVulnerabilityCurse, Spell, AoE, Duration
  Radius: 22
  Mana Cost: (24 to 50)
  Cast Time: 0.50 secRequires Level 24Curses all targets in an area, increasing the physical damage and damage over time they take.Per 1% Quality:
  Cursed enemies take 0.5% increased Physical DamageBase duration is (9-10.9) seconds
  Cursed enemies take (20-29)% increased Physical Damage
  Cursed enemies take 33% increased Damage from Damage Over Time effects
  +(0-10) to radiusPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. does affect the cloud.

Gem level progression

Level			Mana Cost	Base Duration	Chaos Damage per sec	% of Physical Damage as Chaos	Radius	Exp.	Total Exp.
1	4	16	8	2.8	5.3	30%	N/A	0	0
2	6	20	8	2.9	6.7	31%	N/A	841	841
3	9	27	8	3	9.2	32%	N/A	3,099	3,940
4	12	33	9	3.1	12.3	33%	N/A	7,433	11,373
5	16	41	9	3.2	17.7	34%	1	22,895	34,268
6	20	50	9	3.3	24.9	35%	1	49,725	83,993
7	24	58	10	3.4	34.3	36%	1	95,714	179,707
8	28	67	10	3.5	46.7	37%	1	169,595	349,302
9	32	75	10	3.6	62.8	38%	1	283,759	633,061
10	36	83	11	3.7	83.6	39%	2	453,996	1,087,057
11	40	92	11	3.9	110.5	40%	2	703,128	1,790,185
12	44	100	12	4	145	41%	2	1,061,223	2,851,408
13	48	109	12	4.1	189.4	42%	2	2,065,870	4,917,278
14	52	117	13	4.2	246.2	43%	2	2,507,110	7,424,388
15	55	123	13	4.3	298.8	44%	3	2,573,731	9,998,119
16	58	130	14	4.4	361.9	45%	3	7,611,351	17,609,470
17	61	136	14	4.5	437.5	46%	3	13,437,908	31,047,378
18	64	142	15	4.6	527.9	47%	3	25,052,147	56,099,525
19	67	148	15	4.7	636	48%	3	43,869,436	99,968,961
20	70	155	16	4.8	765	49%	4	242,081,178	342,050,139
21	72	159	16	5	847.3	50%	4	N/A	N/A
22	74	N/A	17	5.1	937.4	51%	4	N/A	N/A
23	76	N/A	17	5.2	1036.2	52%	4	N/A	N/A
24	78	N/A	18	5.3	1144.1	53%	4	N/A	N/A
25	80	N/A	18	5.4	1262.1	54%	5	N/A	N/A
26	82	N/A	19	5.5	1390.8	55%	5	N/A	N/A
27	84	N/A	19	5.6	1531.2	56%	5	N/A	N/A
28	86	N/A	20	5.7	1684	57%	5	N/A	N/A
29	88	N/A	20	5.8	1850.3	58%	5	N/A	N/A
30	90	N/A	21	5.9	2030.9	59%	6	N/A	N/A

Quest reward

This skill is given as quest reward for the following quests:

Class	Marauder	Templar	Witch	Shadow	Ranger	Duelist	Scion
Quest
Breaking Some Eggs Act 1

Vendor reward

This skill can be bought at the listed npc vendors after completing the following quests:

Class	Marauder	Templar	Witch	Shadow	Ranger	Duelist	Scion
Quest
Breaking Some Eggs Act 1 Nessa
A Fixture of Fate Act 3 Siosa
Fallen from Grace Act 6 Lilly Roth

Alternate skill effect

Name	Cost	Description
Tentacle Caustic Arrow Effect Tentacle Caustic Arrow EffectCaustic Arrow Skin Stack Size: 20Replaces the standard effect on a Caustic Arrow gem with an area of ethereal purple tentacles.Right click this item then left click a Caustic Arrow Gem to apply it.	120	Replaces the standard effect on a Caustic ArrowCaustic ArrowAttack, AoE, Duration, Chaos, Bow Radius: 20 Mana Cost: (8 to 16) Cast Time: 1.00 sec Projectile Speed: 3260Requires Level 4Fires an arrow which deals additional chaos damage to enemies it hits, and creates a caustic cloud. Enemies in the cloud take chaos damage over time.Per 1% Quality: 0.5% increased Area of EffectBase duration is (2.8-4.8) seconds Deals (5.3-765) Base Chaos Damage per second Gain (30-49)% of your Physical Damage as Extra Chaos Damage Modifiers to Projectile Damage apply to this Skill's Damage Over Time effect +(0-4) to radiusPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. gem with an area of ethereal purple tentacles. Preview

Related helmet enchantments

The following helmet enchantments affect Caustic Arrow:

Name		Effect(s)
EnchantmentCausticArrowDamage1	66	25% increased Caustic Arrow Damage
EnchantmentCausticArrowDamage2	75	40% increased Caustic Arrow Damage
EnchantmentCausticArrowDuration1	66	20% increased Caustic Arrow Duration
EnchantmentCausticArrowDuration2	75	30% increased Caustic Arrow Duration
EnchantmentCausticArrowRadius1	66	8% increased Caustic Arrow Area of Effect
EnchantmentCausticArrowRadius2	75	12% increased Caustic Arrow Area of Effect

Version history

Version	Changes
2.6.0	Caustic Arrow gains 1 additional unit of radius every 5 levels. No longer gain increased area of effect radius.
2.1.0	Poison Arrow has been renamed to Caustic Arrow as part of the poison changes. The damage of this skill has been increased by around 37% at level 1, but reduced by around 42% by level 20. This reduction is more than compensated for by supporting the skill with the new supports. Caustic Arrow's mana costs have been increased, from 5 to 8 at level one, and from 13 to 16 at level 20.
2.0.0	Reduced the mana cost across all levels. Now grants 0.5% increased area of effect radius per 1% of quality (was 1% per 1% quality). Damage increased by approximately 26% at gem level 20.
1.3.0	Poison Arrow can now damage totems.
1.1.2	Damage has been increased by 8% at level 1, scaling up to an increase of 75% at level 15 of the gem.
1.0.6	Poison Arrow's damage has been increased at higher levels. It now does roughly 35% more damage at gem level 15.
1.0.3	Damage progression has been increased. It is now around 15% better at level 15 than it was in 1.0.2.
1.0.2	Early levels of Poison Arrow have had their damage reduced by around 35%.
0.9.13	It now starts off around 85% stronger at level 1 and is about 1% weaker at level 15.
0.9.12	Rebalanced its mana cost progression to reflect the fact that it does damage in a comparable way to Spells.
0.9.9	The size of the Poison Arrow clouds now scale with their Area of Effect radius properly.
0.9.7	Improved the effects of Poison Arrow.
0.9.5g	Fixed a bug where the Poison Arrow cloud would appear where you clicked even if the arrow was stopped before then by a wall.
0.9.5	Fixed Poison Arrow so that damage from the degeneration is scaled properly for PvP.
0.9.4	Increased the damage.
0.9.2	Poison Arrow does more damage at higher levels than before.
0.8.7	Poison Arrow does additional chaos damage on the actual arrow itself now, in addition to the cloud damage.
0.8.5	Added new skill prototype: "Poison Arrow" (Fires an arrow which explodes in a cloud of poison. Enemies who enter the cloud are poisoned for a short time, taking chaos damage)