Caustic Arrow

"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 ranged attack skill that fires an arrow dealing chaos damage and exploding in a cloud of Chaos damage.

Skill Functions and Interactions

Caustic Arrow creates a caustic cloud, which deals chaos damage over time to enemies standing within it. It does not deal Poison damage and is therefore not affected by poison-related passives.

Duration: Skill Duration supports and passives will increase the duration of the caustic cloud.

Explosive Projectile: Caustic Arrow will explode either at the specified location or on the first monster or obstacle encountered. If it hits an enemy, it will deal additional chaos damage based on your weapon damage. Wherever it explodes, it will leave a caustic cloud that causes a debuff.

Multiple Projectiles: Additional projectiles added will cause additional caustic clouds, but multiple clouds will not cause additional debuffs.

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, but multiple overlapping clouds will not cause additional debuffs.

Ranged Attack Totem: Caustic Arrow works with ranged attacks totem since patch 1.0.2.

Projectile Damage: Passive nodes and gems (such as Slower Projectiles) that increase projectile damage will increase both the damage on hit and the area of effect damage.

Concentrated Effect: Concentrated Effect will decrease 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 Iron Grip (Perk) does not affect the caustic cloud damage , because the cloud is not considered as an attack, but the Iron Grip (support gem) grants increased Projectile Damage, which increase the cloud damage.

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

Culling Strike: The increased damage you get from Culling Strike applies to Cloud damage, but the cloud does not kill enemies instantly when they have less than 10% life.

Gem level progression

Template:GemLevelTable |- ! 1 | 4 | 16 | 8 | 2.80s | 5.20 | 30% | 0 | 0 |- ! 2 | 6 | 20 | 8 | 2.90s | 6.52 | 31% | 841 | 841 |- ! 3 | 9 | 27 | 8 | 3.00s | 8.83 | 32% | 3,099 | 3,940 |- ! 4 | 12 | 33 | 9 | 3.10s | 11.70 | 33% | 7,433 | 11,373 |- ! 5 | 16 | 41 | 9 | 3.20s | 16.52 | 34% | 22,895 | 34,268 |- ! 6 | 20 | 50 | 9 | 3.30s | 22.75 | 35% | 49,725 | 83,993 |- ! 7 | 24 | 58 | 10 | 3.40s | 30.77 | 36% | 95,714 | 179,707 |- ! 8 | 28 | 67 | 10 | 3.50s | 41.03 | 37% | 169,595 | 349,302 |- ! 9 | 32 | 75 | 10 | 3.60s | 54.12 | 38% | 283,759 | 633,061 |- ! 10 | 36 | 83 | 11 | 3.70s | 70.72 | 39% | 453,996 | 1,087,057 |- ! 11 | 40 | 92 | 11 | 3.90s | 91.68 | 40% | 703,128 | 1,790,185 |- ! 12 | 44 | 100 | 12 | 4.00s | 118.13 | 41% | 1,061,223 | 2,851,408 |- ! 13 | 48 | 109 | 12 | 4.10s | 151.35 | 42% | 2,065,870 | 4,917,278 |- ! 14 | 52 | 117 | 13 | 4.20s | 192.97 | 43% | 2,507,110 | 7,424,388 |- ! 15 | 55 | 123 | 13 | 4.30s | 230.92 | 44% | 2,573,731 | 9,998,119 |- ! 16 | 58 | 130 | 14 | 4.40s | 275.70 | 45% | 7,611,351 | 17,609,470 |- ! 17 | 61 | 136 | 14 | 4.50s | 328.55 | 46% | 13,437,908 | 31,047,378 |- ! 18 | 64 | 142 | 15 | 4.60s | 390.82 | 47% | 25,052,147 | 56,099,525 |- ! 19 | 67 | 148 | 15 | 4.70s | 464.13 | 48% | 43,869,436 | 99,968,961 |- ! 20 | 70 | 155 | 16 | 4.80s | 550.33 | 49% | 242,081,178 | 342,050,139 |- ! 21 | 72 | 159 | 16 | 5.00s | 616.05 | 50% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 22 | 74 | | 17 | 5.10s | 689.20 | 51% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 23 | 76 | | 17 | 5.20s | 770.58 | 52% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 24 | 78 | | 18 | 5.30s | 861.12 | 53% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 25 | 80 | | 18 | 5.40s | 961.78 | 54% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 26 | 82 | | 19 | 5.50s | 1073.68 | 55% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 27 | 84 | | 19 | 5.60s | 1198.05 | 56% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 28 | 86 | | 20 | 5.70s | 1336.20 | 57% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 29 | 88 | | 20 | 5.80s | 1489.62 | 58% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |- ! 30 | 90 | | 21 | 5.90s | 1659.98 | 59% | class="table-na" style="text-align: center; " | N/A | class="table-na" style="text-align: center; " | N/A |}

Version history

Version	Changes
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.