Alchemical Hydra

The Alchemical Hydra is a level 95 Slayer boss encountered in the Karuulm Slayer Dungeon. In order to fight it, players must be assigned a hydra task. While the Hydra is in the room, players cannot leave through the doors, as they are jammed when this occurs. Teleports will still work, however. The Hydra has a respawn time of 20 seconds. The hydra has four phases, each one beginning upon hitting or going past each 25% health threshold (~275 health). A head will fall off each time this occurs as the hydra roars and changes forms, signifying the start of the next phase.

The hydra attacks with both Magic and Ranged, with the left heads attacking with magic and the right with ranged. In the first two phases, this consists of two instant hits that deal less damage individually. In the last two phases, this will consist of one hit that does higher individual damage. The hydra will begin the fight with either combat style. Regardless if the hits connect or not for the first three phases and after every three auto-attacks, the hydra will sway its heads backwards as a warning indicator that it is changing combat styles. Players should be aware that the Hydra's phase transition animation can override the attack swapping animation, so counting the attacks is still beneficial.

During the first three phases, the hydra's carapace is strengthened and will immensely reduce incoming damage by 75% of what it would have dealt. This must be removed by luring it to the appropriate chemical vent. If takes chemicals from an incorrect vent, its enrage stack will go up, increasing the damage of its attacks. At the start of each phase, the hydra will perform three auto-attacks before performing a special attack.

Requirements & Recommendataions

Stats

Stats required to kill this boss:

• 40+ Prayer for Protection Prayers (95+ recommended for Turmoil, and Soul Split to heal between attacks)
• 80+ Range (If using Ranged)
• 90+ Attack
• 90+ Strength
• 95+ Slayer: To attack the boss.

Auras & Relics

	Divinity (Silver) Your prayer points drain 10% slower.
	Overclocked (Silver) Aura cooldown is reduced by 20% and auras last 10% longer.
	String of Luck (Gold) Offers a 10% luck boost (excludes raids).
	Stroke of Luck (Gold) Offers a 10% chance to double monster drop loot.
	Catch em All (Gold) Offers 50% higher drop rate on all pets. (if pet hunting)
	Master Reverence - Slows down prayer drain and increases prayer restoration from potions by 7%.
	Vampyrism - Gain life points equal to 5% of any damage you deal.
	Penance - Gain prayer points equal to 5% of any damage you receive.

• High Alch runes can be helpful to alch unneeded rune drops and increase gp per run.

Fight & Mechanics

A player fighting the Alchemical Hydra in its poison phase.

A player fighting the Alchemical Hydra in its lightning phase.

A player fighting the Alchemical Hydra in its flame phase.

The Fight

Hydra has four phases. This section explains how to kill it.

1. In this phase, the hydra starts with a green carapace , and should be lured to the red chemical pool. After the first kill, the player should stand right next to the red chemical vat (to the west) so that the Hydra is automatically lured to the red chemical pool as soon as it spawns.
2. Now with a blue carapace, the hydra should be lured to the green chemical pool. After the second kill, the player should stand right next to the green chemical vat (to the north ) so that the Hydra is automatically lured to the green chemical pool as soon as it spawns.
3. Now with a red carapace, the hydra should be lured to the blue chemical pool. If the hydra transitions to the next phase while performing this attack, it ends abruptly. This also includes the tracking fire, but any fires started before the phase transition will still persist as usual. For the duration of the side fires, the hydra also becomes a solid NPC, meaning that it is not possible to walk under it.
4. The final phase has no counter, and it doesn't need to be lured to any pool. In this phase, the Hydra becomes enraged and has a max hit of 55 making it capable of killing players in a single attack as it deals damage twice.

The Mechanics

Hydra attacks in phases of three, which means that you will always face three ranged attacks into three magic attacks. Therefore, it is useful to count each attack to know when to switch prayers to avoid taking damage.

1. In the first phase after the first three attacks, Hydra will fire four poison balls. Players have to move to avoid taking massive damage. After the first special attack, it will repeat doing it after every sixth attack
2. For the second phase, after the first three attacks Hydra will launch an electric ball in the centre of the room, which spawns four lightning strikes at the edges of the room that move towards the player. Players can dodge this by moving by the north vat and quickly moving west, which is especially useful if using ranged. Otherwise players have to run around to avoid the attacks.
3. Throughout the phase, the hydra will occasionally walk to the centre of the chamber and become un-attackable. Upon reaching the centre, it breathes 5x5 layer of fire to the player's sides based on their location before staring down the middle and launching a tracking fire. This tracking fire follows the player's movement, and travels significantly faster the further the player is (or if they start running). Turning off run and walking in a line as the fire trails is the best course of action. Getting hit by any of the fires will result in the player taking up to 20 damage, followed by a subsequent bleed of 5 damage for five hits. It is highly advised to get Hydra onto the blue chemical pool before she walks to the center to kill her as fast as possible.
4. For the final phase Hydra will use the similar special as in the first phase but this time will only fire one poison blob after the first three attacks. Simply dodge it by moving one step in any direction, and pray protection from ranged or magic depending on Hydra's style. Keep in mind she will keep firing one poison blob after every six attacks once it has occured once.

Equipment

Slot	Item (most effective → least effective)
	Slayer helm (i)	Inquisitor's great helm	Neitiznot faceguard	Statius's full helm	Serpentine helm or Helm of Neitiznot
	Amulet of torture	Amulet of fury	Strength amulet	N/A	N/A
	Infernal cape	Fire cape	Max cape	N/A	N/A
	Inquisitor's hauberk	Statius's platebody	Bandos chestplate	Fighter torso	Dharok's platebody (or Barrows platebodies)
	Inquisitor's plateskirt	Statius's platelegs	Bandos tassets	Obsidian platelegs	Dharok's platelegs (or Barrows platelegs)
	Dragon hunter lance	Ghrazi rapier	Blade of Saeldor (c)	Chaotic rapier	Abyssal tentacle / Abyssal vine whip / Abyssal whip
	Avernic defender	Dragon defender	Dragonfire shield	Rune defender	Crystal shield
	N/A	N/A	N/A	N/A	N/A
	Ferocious gloves	Goliath gloves	Barrows gloves	Dragon gloves	Rune gloves
	Primordial boots	Steadfast boots	Dragon boots	Guardian boots	Bandos boots
	Berserker ring (i)	Ring of Suffering (i)	Berserker ring	Ring of wealth (i)	Ring of wealth
	Dragon dagger	Vesta's longsword	Bandos/Saradomin Gosword	Dragon warhammer	Any other melee spec weapon

• Strength bonus is preferred over prayer bonus for melee
• Inquisitor's armour provides an extra +2 prayer bonus over bandos making it slightly better if you are flicking correctly. Bandos has more defence to tank range hits without prayer.
• Melee with dragonhunter lance is similar dps to killing with blowpipe if you have a good strength bonus
• Learning the flame phase will speed up kills a lot

Inventory

• 1-2 Overloads (or super combat potions)
• 1-2 Antidote++
• 8-15 Prayer/Super Restore Potions (Depending on if you use Soulsplit or not)
• Fill your inventory with the rest high healing food like, sharks, manta rays or rocktails
• Special attack weapon

Slot	Item (most effective → least effective)
	Slayer helm (i)1	Armadyl helmet	Royal coif	Serpentine helm	Robin hood hat or Blessed coif
	Necklace of anguish	Saradomin's murmur	Amulet of fury	Amulet of glory
	Ava's assembler	Ava's accumulator	Ranging cape	Ava's attractor	N/A
	Armadyl chestplate	Karil's leathertop	Royal d'hide body	Blessed body	Black d'hide body
	Armadyl chainskirt	Karil's leatherskirt	Royal d'hide chaps	Blessed chaps	Black d'hide chaps
	Toxic blowpipe	Zaryte crossbow	Chaotic crossbow	Dragon crossbow or Rune Crossbow
	Eagle-eye kiteshield	Dragonfire ward	Twisted buckler	Crystal shield	God book
	Ruby dragon bolts (e) + Diamond dragon bolts (e)	Ruby bolts (e) + Diamond bolts (e)	N/A	N/A	N/A
	Swift gloves	Zaryte vambraces	Barrows gloves	Black d'hide vambraces
	Pegasian boots	Glavien boots	Ranger boots	Blessed boots	Boots of brimstone
	Archers ring (i)	Ring of Suffering (i)	Archers ring	Ring of wealth (i)	Ring of wealth
	Saradomin godsword / Eldritch nightmare staff	File:Crystal spear.png Crystal spear	Toxic blowpipe	Dragon claws	Dragon dagger

Inventory

• About 4–20 prayer potions or super restores. Each kill should take around 2:00-2:30 with a toxic blowpipe, so generally 2-3 doses are required per kill (slightly less for twisted bow users).
• Some food; 4-10 sharks or manta rays. Saradomin brews are also an option, though ranging potion usage must be carefully considered for this case.
• Antidote++
• Divine ranging potion, ranging potion, or bastion potion (note that the latter is entirely superfluous, as due to prayers almost all damage taken in the fight can be mitigated)